Search

A low‐profile wideband 8‐antenna array for future 5G New Radio (5G NR) mobile devices is studied. Each array element has a size of 16.85 mm × 4.6 mm, and the height of the frame is only 5 mm. The array element is composed of a driven element coupled‐fed by a T‐shaped feeding element and a shorting element. The driving element and the shorting element enable the antenna to obtain dual resonance modes, while the T‐shaped feeding structure can improve the impedance matching. The 10‐dB impedance bandwidth (3.27–4.24 GHz) of the proposed 8‐antenna array can completely cover the 5G Sub‐6GHz NR Band n77/n78. The measured antenna efficiency of each array element was higher than 50%. Good isolation of >13 dB was achieved between adjacent array elements due to the introduction of a modified decoupling structure. Besides achieving a desirable ECC of <0.06, the calculated channel capacities of the 8 × 8 multiple‐input multiple‐output system working across the bands of interest can reach up to 38.8 bps/Hz. [ABSTRACT FROM AUTHOR]

A coplanar waveguide (CPW) fed polarization reconfigurable antenna for WLAN 2.4 GHz operation is studied. To achieve reconfiguration between left‐hand circular polarization (LHCP), right‐hand circular polarization (RHCP), and linear polarization (LP) with broad CP and LP operating bandwidths, the technique of switching only two PIN diodes embedded between the CPW feeding line and an open square‐ring radiating element is introduced. As the radio frequency (RF) and direct current (DC) signals must be fed from the same feeding line (input port), during the experiment, an additional Bias‐Tee element is introduced to the input port for combining the two signals. [ABSTRACT FROM AUTHOR]

In this article, a low profile four element coplanar waveguide ground (CPWG) fed multiple input multiple output (MIMO) antenna having designed footprint of 1.65 × 1.65λ (at 5.5 GHz) is developed for Wi-Fi 5 (5.15–5.85 GHz) and Wi-Fi 6 (5.925–7.125 GHz) access point and repeater applications to satisfy the increasing demands of wireless communication. Each antenna element that is applied for MIMO configuration, consists of a Y-shaped monopole top-loaded by an inverted-C structure (ICS), in which the two open-ends of the ICS are coupled to the two-side ground forming a symmetrical ground-coupled loop antenna structure. Further four identical antenna elements are arranged in a sequential clockwise manner to suppress the mutual coupling among antenna elements forming a 4-port MIMO antenna structure. To enhance the isolation between the adjacent antenna elements, the partial ground planes of all 4 elements are meticulously connected by a whirligig isolating structure. The proposed 4-port MIMO antenna is fabricated and tested for the validation of design, scattering and radiation performances as well as MIMO diversity parameters. Besides yielding a very wide measured 10-dB impedance bandwidth of 35.45% (5.15–7.37 GHz) with isolation better than 25 dB, the designed 4-port MIMO antenna has also demonstrated acceptable gain and radiation efficiency of 4 dBi and 74%, respectively. Furthermore, desirable MIMO performances like envelope correlation coefficient (ECC) less than 0.008, diversity gain (DG) ~ 10 dB and channel capacity of around 21 bps/Hz are also calculated across the bands of interest. [ABSTRACT FROM AUTHOR]

A circularly polarized (CP) meander loop antenna used in the unmanned aerial vehicle (UAV) satellite navigation system is proposed. The planer size of the proposed antenna is 45.6 × 38.4 mm2 and it was printed on a thin flexible substrate with a thickness of only 0.063 mm. Thus, it has the advantages of a lightweight, low profile, and ease in manufacturing. The proposed antenna design utilizes a loop antenna and has applied a perturbed element into the loop to excite two equal amplitude electric fields with a 90° phase difference, thereby exciting a good CP radiation. The measured 10‐dB impedance bandwidth of the proposed antenna was 9.3% (1.48–1.624 GHz), and its corresponding 3‐dB axial ratio (AR) bandwidth was 2.3% (1.555–1.591 GHz). The CP operating band of the proposed antenna can cover the GPS L1, Galileo E1, and Beidou B1 band (1.559–1.591 GHz). [ABSTRACT FROM AUTHOR]

A novel maze shaped multiband monopole antenna with a miniaturized size of only 6 × 4 × 1.6 mm3 is proposed. To further achieving excellent radiation performances across the desired operating bands, an air‐gap is set between the proposed antenna and system ground. To assess the performances of the antenna, simulations are initially carried out by loading a 1.6 mm thick nonconducting Polycarbonate material (analogous to an air‐gap) between the antenna and system ground, and a simplified equivalent circuit (EC) model of the proposed antenna is also derived. The proposed antenna has excited two different resonance frequencies, in which the lower band (fL) and upper band (fU) can yield broad 10‐dB impedance bandwidths of 6.5% (2.37‐2.53 GHz) and 16% (5.05‐5.90 GHz), respectively. Furthermore, desirable gain and radiation efficiency of 2.85 to 6.40 dBi and 57% to 85%, respectively across the two operating bands were also achieved. A practical experiment is also carried out by installing the proposed antenna into a real laptop computer (L412 Think Pad Lenovo). [ABSTRACT FROM AUTHOR]

A very small size radio frequency identification (RFID) tag antenna specifically designed for racing pigeon ring applications is proposed. The structure of this UHF tag is a closed-loop type printed on a 30 × 8 mm2 polyimide film of thickness 0.063 mm. Thus, it can be wrapped into a double layer plastic cylindrical ring of size similar to those used for racing pigeon. By simply tuning the inner width of the loop, good conjugate matching between the tag chip input impedance and the tag antenna can be achieved. When mounted onto a real preserved dried pigeon feet specimen, the measured impedance bandwidth of the tag antenna was 901-929 MHz. Further experimental results have also shown that the proposed antenna has a maximum reading range of up to 50 cm. [ABSTRACT FROM AUTHOR]

A novel uniplanar antenna design for tablet/laptop applications is proposed. The proposed antenna with a size of 68 × 12 × 0.8 mm3 is comprised of three strip sections, namely, the feeding strip, parasitic shorted strip, and tuning stub strip (or printed LC matching circuit). Five resonant modes are induced by the proposed antenna, and they are combined to yield two wide operating bands that have 6-dB return loss bandwidths of more than 50% (695-1190 MHz and 1690-2930 MHz). Thus, the proposed antenna can easily cover the entire LTE/WWAN operations working in the 698-960 MHz and 1710-2690 MHz bands. Besides demonstrating good radiation efficiency of more than 60% for the two wide operating bands, the proposed antenna also exhibits reduced ground effects, in which reducing the ground size will not deteriorate the antenna's performances. [ABSTRACT FROM AUTHOR]

The design of a simple ultrahigh frequency RFID (radio frequency identification) reader antenna that can operate within the North America RFID band (902-928 MHz) is studied. To generate circular polarization (CP) radiation in this band, a novel method of loading two narrow open-ended slots (slits) into an eccentric annular slot patch is proposed. To allow optimum impedance matching with enhanced CP bandwidth, the radiating patch is loaded to an L-shaped ground plane. From the experimental results, the proposed antenna can yield an impedance bandwidth (10-dB return loss) between 650 MHz to 1125 MHz, while good CP bandwidth (3-dB axial ratio, AR) from 901 MHz to 930 MHz is also attained. Furthermore, gain level and efficiency of more than 7.8 dBic and 90%, respectively, were also measured. By simply removing one of the slits, this proposed antenna can also be modified to operate within the China (840-846 MHz) and European (865-868 MHz) RFID band. [ABSTRACT FROM AUTHOR]

A low profile annular-ring patch antenna with circularly polarized (CP) radiation for radio frequency identification (RFID) reader applications in the ultra-high frequency (UHF) band (922-928 MHz) is presented in this article. Perturbation method is applied by loading a pair of triangular open-notch into the outer circumference of ring patch, and good impedance matching can be determined by using the coupled feeding technique. The overall size of this proposed antenna is 150 mm × 150 mm × 10.4 mm. The measured results show desirable 10-dB impedance bandwidth and 3-dB axial ratio (AR) bandwidth of 3.5% (908-941 MHz) and 0.65% (922-928 MHz), respectively. Stable antenna peak gain and efficiency of 7.2 dBic and 87% are also exhibited, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT A microstrip-fed circular slot antenna design is proposed. To excite good CP (circularly polarized) radiation, the technique of loading a cross patch (with unequal arm lengths) into the circular slot is initially applied. Here, good impedance matching can be further attained by dividing the cross patch into two equal sections with a gap loaded in between them, in which this gap will induce a capacitive loading effects on the proposed antenna. The measured results shown that the proposed antenna has 10 dB impedance bandwidth of 36.4% (2116-3124 MHz), and its corresponding CP bandwidth (along 3 dB axial ratio, AR) was 12.3% (2345-2655 MHz). In addition to that, the proposed CP slot antenna has also yielded peak gains of more than 3.3 dBic across the CP bandwidth. Detailed process of designing the proposed CP slot antenna is explicitly shown, and vital parametric studies were also conducted by simulation. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:715-720, 2016 [ABSTRACT FROM AUTHOR]

ABSTRACT A microstrip-fed conventional annular ring slot (ARS) antenna with linear polarization (LP) is initially studied. To generate two orthogonal degenerate modes for circular polarization (CP) radiations, two identical meandering perturbation slots (MPS) are symmetrically loaded into the ARS. By further incorporating a PIN diode switch across each MPS, the proposed antenna can switch between left-hand CP (LHCP), right-hand CP (RHCP), and LP. All three polarizations have shown good impedance bandwidth and broad CP bandwidth that can satisfy the wireless local area network (WLAN) 2.4-GHz operating band (2400-2480 MHz). Furthermore, desirable gains of 1.8-2.0 dBi and 2.40-2.84 dBic are also exhibited at LP and LHCP/RHCP, respectively. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:110-120, 2016. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel complementary-conducting-strip (CCS) coupled-line (CL) design is proposed to achieve compact size by applying two-dimensional layout and standard gallium-arsenide (GaAs) thin-film technology. To obtain high coupling and satisfy the design rules of GaAs process, mixed-couple mechanism with edge and broadside coupling are also used. A CCS CL-based Ka-band 3-dB directional coupler is fabricated using WIN 0.15-μm GaAs pseudomorphic high electron mobility transistor technology. Experimental results show that the proposed directional coupler can cover the entire Ka-band (26-40 GHz) with through and coupling of approximately 3.7 ± 0.25 dB, and isolation of better than 13 dB. In addition, the phase difference between the two output ports is approximately 90° ± 5°. The occupied area of the prototype (without I/O networks) is only 220 × 220 μm2. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:21-26, 2016. [ABSTRACT FROM AUTHOR]

ABSTRACT A dual-band planar long term evolution (LTE) antenna design is initially proposed. The size of this proposed antenna is 40 mm × 15 mm × 0.8 mm, and its structure is meticulously designed to achieve reduce ground effects, so that the ground plane size can be altered without affecting the antenna's performance. The 6-dB impedance bandwidths of both lower and upper operating bands of proposed antenna are 13.1% (695-790 MHz) and 37.6% (2200-3120 MHz), respectively. Minimum radiation efficiencies of up to 56% are also exhibited within the three LTE bands (LTE 700/2300/2600 MHz). This proposed antenna is later used as a two-antenna multiple input multiple output (MIMO) system for laptop computer application, and because of its reduced ground effects, good envelope correlation coefficient (ECC) of less than 0.14 and 0.0022 are measured across the lower and upper operating bands, respectively. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:80-87, 2016. [ABSTRACT FROM AUTHOR]

A microstrip-fed reconfigurable eccentric annular ring slot (EARS) antenna with switchable polarization is proposed. To generate orthogonal circular polarization (CP) radiations, two identical perturbation slots (PSs) are loaded below the eccentric ring-shaped slot. By incorporating a PIN diode switch across each PS, the proposed antenna can switch between left-hand CP (LHCP), right-hand CP (RHCP), and linear polarization (LP). All three polarizations have shown good impedance bandwidth and broad CP bandwidth that can cover the WLAN 2.4 GHz operating band (2400–2480 MHz). Furthermore, desirable gains of 2.49–2.82 dBi and 2.94–3.24 dBic are also exhibited at LP and LHCP/RHCP, respectively. [ABSTRACT FROM PUBLISHER]

ABSTRACT The design of a small size 50 × 50 mm2 coplanar waveguide-fed square ring slot antenna is studied. To attain circular polarization (CP) radiation with broad 3-dB axial ratio (AR) bandwidth that can cover the worldwide interoperability for microwave access 2.3 GHz (2305-2320 MHz, 2345-2360 MHz) and wireless local area network 2.4 GHz (2400-2480 MHz) bands, a novel technique of extending a C-shaped branch from the vertical monopole is proposed. Good impedance matching and CP performance was achieved by further extending a vertical tuning strip from the C-shaped branch. From the measured results, 10-dB impedance bandwidth and 3-dB AR bandwidth of 63.89% and 7.93% were achieved. Furthermore, stable gain variation of approximately 2.7 dBic and radiation efficiency of more than 85% were also exhibited across the bands of interest. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:886-891, 2015 [ABSTRACT FROM AUTHOR]

ABSTRACT A small size (20 × 38.5 × 0.8 mm3) coplanar waveguide (CPW)-fed monopole antenna for wireless local area network and worldwide interoperability for microwave access applications is proposed. To achieve tripleband operation, the proposed monopole antenna is designed with a modified symmetrical U-shaped printed structure attached with a parasitic element behind it. Good impedance matching is also attained by loading two dissimilar notches separately into the two CPW ground planes. The measured 10-dB impedance bandwidths of the three operating bands (fL, fM, and fH) are 16.96% (2.105-2.495 GHz), 28.72% (3.22-4.30 GHz), and 23.32% (4.895-6.125 GHz), respectively, and all bands of interest have yielded peak gain and radiation efficiency of more than 2.7 dBi and 65%. Detail process of designing the proposed antenna is explicitly shown, and vital parametric studies were also conducted by simulation. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:342-348, 2015 [ABSTRACT FROM AUTHOR]

A microstrip-fed circular ring slot antenna (CRSA) with a fundamental mode at 2.45 GHz is initially studied. To suppress the additional harmonic modes excited by the ring slot, a single inverted U-shaped slot (or defected ground structure, DGS) is integrated into the CRSA. Through this, harmonic suppression over a wide bandwidth (approximately between 3 and 9 GHz) is achieved. This DGS can also be applied to other microstrip-fed ring slot antennas, such as square and triangular ring slot antennas. [ABSTRACT FROM PUBLISHER]

The design of a switchable microstrip-fed half annular ring slot antenna for multi-frequency operation is proposed. By incorporating three switches along the meandered tuning stub that is loaded on top of the half circular patch located within the circular slot, easy reconfigurability of four frequency bands over a frequency ratio of approximately 1.7:1 can be achieved. Furthermore, the proposed antenna structure does not require additional DC biasing circuit. Simulation and measurement results have demonstrated that the four frequency bands can exhibit good impedance matching, stable radiation patterns and desirable gains. [ABSTRACT FROM PUBLISHER]

ABSTRACT A microstrip-fed slot antenna design for wireless local area network 2.4/5 GHz applications is proposed. To achieve dual-band operation that composed of four resonant modes located at approximately 2.28, 2.69, 5.36, and 5.94 GHz band, three separate slots are embedded into the ground plane, in which two of the slots are devised as step-impedance types, and one of the slots is an L-shaped slot type. By meticulously arranging the positions of these three slots located above the microstrip-fed line, two broad operating bands that operate between 2140-2750 MHz (∼25%) and 5050-6160 MHz (∼20%) are achieved. Detail process of designing the proposed antenna is explicitly shown, and vital parametric studies were also conducted by simulation. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:983-988, 2014 [ABSTRACT FROM AUTHOR]

ABSTRACT A coupled-fed antenna that combines the long term evolution operation with the wireless wide area network operation is proposed. The antenna is mainly composed of a T-shaped radiator linked to the ground plane via a narrow meandered line. Good impedance matching throughout all bands of interest is achieved by embedding a C-shaped coupling structure into the narrow meandered line, followed by protruding a small stub at the right bottom corner (vertical structure) of the T-shaped radiator. Furthermore, by reconstructing the coupled-fed structure as a halved-tapered fed design, two wide operating bands that operate between 680 and 1380 MHz (68%), and 1550 and 2830 MHz (58.4%) are achieved. The process of designing the proposed antenna is explicitly shown, and parametric studies were carried out by simulation. Typical experimental measurements were also conducted and compared to the simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1851-1856, 2013 [ABSTRACT FROM AUTHOR]

A compact (31 mm\,\times \,7 mm\,\times\,0.8 mm) uniplanar antenna designed for wireless local-area network (WLAN) operations in laptop applications is proposed. To achieve triple-band (2.4/5.2/5.8 GHz) WLAN operation, the structure of the proposed antenna is devised as an asymmetric dipole type, in which the 2.4/5.2 GHz operating bands are excited along the meandered feed line connected to a rectangular radiating element, and the excitation of the 5.8 GHz band comes from its asymmetric counterpart (with C-shaped parasitic strip). Interestingly, the proposed triple-band antenna can be reduced to a dual-band (2.4/5.2 GHz) one by simply tuning the length of the C-shaped parasitic strip. The simulated effects on the antenna performances by tuning the various vital parameters have been studied and experimentally verified. [ABSTRACT FROM PUBLISHER]

A square-shaped microstrip RFID tag antenna designed for 915 MHz band is proposed. The antenna is capacitively excited by a dual-offset coupling feed network with one of the feed lines a quarter-wavelength longer than the other. By selecting appropriate dimensions for the coupled lines and feed-lines, along with desirable coupling distance between the coupled line and square patch, the input impedance of the proposed tag antenna can be easily controlled, which results in excellent impedance matching. Moreover, by incorporating the dual-offset feed technique with the method of embedding a cross slot of unequal arm lengths into the square patch, the bandwidth of the circularly polarized (CP) operation can be enhanced. The measured 6-dB return-loss bandwidth of the tag antenna is 25 MHz (902–927 MHz), and its corresponding 3-dB axial-ratio (AR) bandwidth is 20 MHz (903–923 MHz). Further experimental results show that the proposed tag antenna can provide slightly better reading range and gain when mounted on a large metallic surface. [ABSTRACT FROM PUBLISHER]

An electroconductive polyester yarn is used to fabricate an embroidered wearable monopole antenna for ultrawideband applications.Here, the structure of this embroidered antenna is a common coplanar waveguide-fed circular disk monopole antenna. From the experimental results, a 10-dB impedance bandwidth from 2.7 to 10.62 GHz is measured, while steady gains with near omnidirectional radiation patterns are exhibited within the bands of interest. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2597-2600, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27133 [ABSTRACT FROM AUTHOR]

The design of a simple UHF (ultrahigh frequency) RFID (radio frequency identification) reader antenna that operates within the 900 MHz band (902–928 MHz) is studied. To generate circular polarization (CP) radiation, a novel method of loading a semicircular slot into the main circular radiating patch is proposed. To allow optimum impedance matching with enhanced CP bandwidth, the L-shaped probe-feed technique is employed in this design. From the experimental results, besides achieving a gain level of more than 7 dBic, the proposed antenna can also yield an impedance bandwidth (10-dB return loss) from 880 to 1100 MHz, while good CP performances between 901 to 930 MHz are exhibited. To further validate the experimental results, parametric studies are also carried out via simulation. [ABSTRACT FROM PUBLISHER]

This study designed a 2\,\times\,2 circular disc array antenna with omnidirectional radiation pattern and polarization diversity. Each disc element was located above a circular slot fed by an L-shaped strip, in which the switching between two orthogonal linear polarizations (LP) and circular polarization (CP) were realized by controlling two pin diodes. To allow conical beam for all polarization senses, a meticulously designed cross-shaped feeding network is proposed, and besides showing a sufficient 10 dB return loss bandwidth that covers the 2.4 GHz band of WLAN operation, good cross-polarization level (XPL) were measured when the array operated in all available polarization senses. [ABSTRACT FROM PUBLISHER]

Two novel array antennas (3 \times 2 and 3 \times 3) with broadband and high gain characteristics are proposed for the application of WiMAX base station. To maintain the same electric current intensity with identical phase for each array element, an asymmetrical feed-network which composed of microstrip T- junctions with 2:1 power ratio, quarter-wavelength impedance transformers, and 180^\circ phase shifters are devised, which in turn exhibits a desirable gain of more than 17 dBi at boreside direction for the proposed array antennas. Furthermore, by embedding a U-slot into all array elements, enhanced operating bandwidth measured along 14-dB return loss can be achieved, so that the WiMAX band operating between 3.3 and 3.8 GHz can be covered. [ABSTRACT FROM PUBLISHER]

The design of a hybrid antenna with double layer structures that allow multiband operation in the global system for mobile communications/digital communication systems/personal communication system/universal mobile telecommunications system and wireless local area network band bands is presented. By combining the resonant modes excited separately by the upper layer planar inverted-F antenna structure (0.88, 0.97, and 1.18 GHz) and lower layer monopole antenna type structure (1.38, 1.76, and 2.45 GHz), a dual-frequency operation with broadband characteristics can be observed, whereby the lower and upper frequency bands are operating between 0.86 and 1.00 GHz and between 1.15 and 2.63 GHz, respectively. From the experimental results, stable gain and good radiation efficiency are also exhibited within the bands of interest. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1543-1548, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26863 [ABSTRACT FROM AUTHOR]

A compact size slot antenna designed for ultrawideband (UWB) applications is proposed.The slot embedded into the antenna was comprised an open-ended hemicircular slot and a narrow rectangular slot. To achieve good impedance matching within the desired band of interest, the 50 Ω microstrip feed-line is loaded with an elliptical slot, while an extended substrate was protruded above the upper edge of the antenna. The experimental results such as return losses, radiation patterns, and gain properties are studied, and good characteristics are demonstrated. Typical frequency domain responses are also measured to ensure that the proposed antenna can provide stable signal transmission within the UWB spectrum. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:86-91, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26514 [ABSTRACT FROM AUTHOR]

A compact size (15 × 40 mm2) microstrip-fed printed planar inverted-F antenna (PIFA) for mobile applications operating in the GSM/DCS/PCS/UMTS/WLAN and WiMAX bands is proposed. The main structure of this antenna is simply a double-folded PIFA with two wide open-ended radiating sections. By tuning the dimensions of the shorter open-ended section, optimum impedance matching can be achieved, while additional slits loaded to the longer open-end section are for the inclusion of universal mobile telecommunications system band. To allow shifting of the higher frequencies modes so that a wide impedance bandwidth from 5 to 6 GHz can be achieved, the technique of adjusting the position of the shorting post horizontally along the ground plane is also introduced. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2952-2960, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26429 [ABSTRACT FROM AUTHOR]

A novel microstrip-fed polygon slot antenna with dual-band operation for WLAN (Wireless Local Area Network) applications in the 2.4/5.2/5.8 GHz bands is proposed. The polygon slot is formed by embedding two right-angle triangular ground patches into both upper-corners of the rectangular slot. To allow the excitation of three resonant modes located exactly around 2.4, 5.2, and 5.8 GHz bands, besides tuning the length of the hypotenuse of the triangular ground patches, an L-shaped slit is also loaded into the rectangular radiating element. The design of this proposed antenna via simulation is illustrated in detail, and typical experiments were performed on the fabricated prototype. From the experimental results, the lower band measured along VSWR 2:1 operates from 2.36 to 2.63 GHz, while a broad upper band from 4.98 to 6.8 GHz is also observed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1394-1398, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26018 [ABSTRACT FROM AUTHOR]

A printed compact size folded inverted-F antenna with simple configuration for mobile handset operating within the global system for mobile communication/personal communication system/digital communication system bands is initially proposed.To additionally cover the wireless local-area network frequency spectrum at 2.4 GHz, a narrow stub is protruded from the printed shorting wall. The excitation of these operating bands with desirable bandwidth is achieved by feeding a 50-Ω microstrip line to the folded radiating element through a via hole. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1045-1050, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25919 [ABSTRACT FROM AUTHOR]

A novel coplanar rectangular slot antenna with dual band operation is proposed.By loading two dissimilar inverted L-shaped slit into the rectangular radiating element, broad impedance bandwidth at both lower and upper operating bands are achieved to allow the operation for 2.4/5.2/5.8 GHz wireless local area network and 2.6/3.5/5.5 GHz worldwide interoperability for microwave access bands. The design evolution of this proposed antenna by simulation is clearly demonstrated, and a prototype was fabricated and experimentally investigated. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:987-991, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25936 [ABSTRACT FROM AUTHOR]

A compact size planar microstrip-fed monopole antenna designed for mobile handset applications is proposed. To operate at global system for mobile communication (GSM)/global positioning system/digital communication system/personal communication system/universal mobile telecommunications system and 2.4-GHz wireless local-area network bands, a hybrid technique of joining the horizontal section of a T-monopole to an open-loop back coupling strip and loading a pair of monopole slot into the ground plane is used. Two operating bands are observed (along 3:1 VSWR) with the lower band covering only the GSM application, while the wide upper operating band covers the remaining applications. The effects on the antenna performances by tuning the various vital parameters have also been studied. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:910-915, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25889 [ABSTRACT FROM AUTHOR]

A novel coplanar equilateral triangular-ring slot antenna with dual frequency operation is proposed for WLAN (Wireless Local Area Network) system in the 2.4/5.2/5.8 GHz operating bands.Impedance matching for both lower and upper operating bands at 2.4 and 5.8 GHz, respectively, are achieved by capacitively loading the inner triangular patch. To excite the 5.2-GHz band, two T-shaped slits are inserted into the triangular patch. The design flow of this antenna is clearly illustrated, and a prototype was constructed and experimentally investigated. Good radiation patterns and stable gain variation are measured for all operating bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2775-2780, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25601 [ABSTRACT FROM AUTHOR]

The numerical design method for a microstrip-fed circular-disc monopole (CDM) antenna operating within the ultrawideband (UWB) from 3.1 to 10.6 GHz is initially studied. By simply embedding a pair of U-shaped slots into the ground plane, a band-rejection (band-notch) function at around 5 GHz is achieved. For impedance matching and fine tuning of this proposed antenna, a small rectangular slit is inserted at the top centre of the ground plane. Except within the rejection band, the gain and time-domain characteristics of this antenna has successfully demonstrated that it is applicable to any high data rate short-range wireless communication system that requires a stable signal transmission in the UWB application. The performances of a common UWB CDM antenna without band-rejection function and a similar one with a slot loaded in the radiating circular patch are also investigated and compared with the proposed antenna. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1607–1613, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24379 [ABSTRACT FROM AUTHOR]

Abstract: The characteristics of full and half-size V-slotted triangular patch antennas with shorting walls are investigated and compared in this paper. Both the antennas are dual-frequency radiate elements and they possessed impedance bandwidth of more than 8% at each operating frequency. For the full-size case, the radiation patterns at the lower and higher operating frequencies are conical and broadside, respectively. In comparison, both the operating frequencies of the half-size case exhibited the same broadside radiation patterns. Details of the measured and simulated results are presented and discussed. [Copyright &y& Elsevier]

The design of a dual and triple-band planar inverted-F antenna (PIFA) is proposed for WLAN 802.11 a/b/g applications. Dual-band operation is achieved by simply truncating one of the top rectangular radiating plate's corners, and wide bandwidth for the upper-band is obtained by applying an additional small rectangular slit. By further extending the slit length, a triple-band operation can also be achieved with a maximum gain of around 5 dBi. Simulated results are provided to validate the measured results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2159–2162, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22682 [ABSTRACT FROM AUTHOR]

The compact designs of a shorted triangular patch antenna embedded with a V slot are proposed and studied. A broadband V-slotted triangular patch antenna with one shorting wall is initially constructed as a reference. By inserting an additional shorting wall to this reference antenna, a new broadband operation can be obtained and its operating frequency is decreased by 22%, which corresponds to a reduction of 40% in the antenna area. The antenna area can be further reduced by symmetrically halving the patch size, and it is found that the impedance bandwidth of the broadband operation demonstrated no obvious variation and the operating frequency is only increased by around 8%. Details of the antenna designs and obtained results are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 34–37, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22061 [ABSTRACT FROM AUTHOR]

The characteristics of circular-polarization (CP) square-ring microstrip antennas loaded with superstrate are studied in this paper. Firstly, several CP antenna prototypes with various substrate thicknesses and inner-slot sizes are designed, and they are excited by a coupling-strip feed in order to overcome the high-impedance problem of the square-ring microstrip antenna. Then, superstrates with different thicknesses and permittivities are attached to the antenna prototypes in order to evaluate their effects on the CP performances. The experimental results show that the effects are more obvious for the square-ring microstrip antenna with a larger inner-slot size. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 567–570, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21231 [ABSTRACT FROM AUTHOR]

The design of a square-shaped patch antenna loaded with an Olympic-like logo slot for 900 MHz UHF RFID reader applications is studied.To achieve good circularly polarized (CP) radiation, an additional narrow perturbation slot is also loaded centrally across the logo. By further applying the L-shaped probe-fed method, desirable 3-dB Axial Ratio (AR) and 10-dB impedance bandwidth of 3.72% and 30%, respectively, can be achieved. From the experimental results, gain level and efficiency of more than 6 dBic and 89% were also measured, respectively. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1358-1360, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27591 [ABSTRACT FROM AUTHOR]

The design of a compact coplanar waveguide-fed monopole antenna partially surrounded and coupled by a folded ground strip is presented. By properly tuning the gap between the monopole antenna and the ground strip, it is able to operate in the 5-GHz band for wireless application. From the experimental results, a resonant mode excited at around 5.5 GHz is observed with 10-dB bandwidth measured from 4.88 to 6.3 GHz. Good radiation patterns with near omnidirectional pattern in the azimuth plane are also observed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26330 [ABSTRACT FROM AUTHOR]

A compact size, coplanar waveguide (CPW) fed two‐antenna multiple input multiple output (MIMO) with high isolation and excellent impedance matching operating in n77/n78/n79 5G NR sub‐6 GHz/Wi‐Fi‐5/V2X/DSRC/Wi‐Fi‐6/INSAT‐C is proposed for future wireless applications. Each antenna element is a CPW‐fed antenna type composed of an "inverted‐A," "y‐shaped," and "small extended stub" structures. The two‐antennas are deployed in the same orientation at an edge‐to‐edge distance of 0.06λ (λ represents free‐space wavelength at 3.70 GHz) on a shared rectangular substrate having designed footprint of 0.57λ × 0.39λ. To attain high isolation of greater than 20 dB in the desired bands of interest, a novel comb‐shaped isolating structure is deployed between the two antenna elements. From the measured results, the proposed MIMO antenna has exhibited wide 10‐dB impedance bandwidth of 88.57% (3.00‐7.70 GHz), good gain above 3 dBi and efficiency larger than 78% throughout the desired operating bands. Moreover, the MIMO diversity performance metrics including envelope correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), channel capacity and channel capacity loss (CCL) are also achieved. [ABSTRACT FROM AUTHOR]

The authors propose an innovative double‐Xi‐shaped Chinese character artistic antenna backed by a high‐order‐mode cavity for 5G millimetre‐wave (mm‐wave) applications. The initial double‐Xi‐shaped microstrip antenna element is designed by using characteristic mode theory, and stable gain can be obtained across the whole 5G mm‐wave frequency band. By employing a slotted cavity with TE230 high‐order‐mode to excite 2×2 antenna subarray, a high gain of 13.2 ± 0.8 dBi and a high isolation better than 45 dB without additional feeding networks can be simultaneously achieved. To further improve the gain for reliable transmission, a 4×4 dual linearly polarised (LP) antenna array is also designed and fabricated. Measured results show that a wide frequency bandwidth of 11.45% (24.7–27.7 GHz) with a peak gain of 19.2 dBi and a high isolation of 33 dB is realised for the dual LP antenna array. The proposed method provides a simple and efficient prediction‐theory way to design artistic antenna for the first time, which solves the problem of designing specific‐shaped antenna without theoretical support. [ABSTRACT FROM AUTHOR]

In this article, a three‐port circularly polarized (CP) multiple‐input multiple‐output (MIMO) antenna for wireless local area network (WLAN) application with pattern and polarization diversity is proposed. The proposed MIMO antenna system comprises of a broadside CP antenna element with a T‐shaped slot and two endfire CP antenna elements. Good impedance bandwidth of 16.9% and 5.5% are achieved by the broadside CP antenna and endfire CP antenna, respectively, and their corresponding axial ratio (AR) bandwidth is 7% and 10.47%. The isolation between the different antenna elements is better than 20 dB, and the polarization purity for all CP antenna is more than 25 dB along with the maximum radiation. [ABSTRACT FROM AUTHOR]

A metal‐frame‐integrated eight‐antenna array operating in the long term evolution bands 41/42/43 (2.496 GHz‐2.69 GHz, 3.4 GHz‐3.8 GHz) for future fifth generation multiple‐input multiple‐output (MIMO) applications in smartphones is presented and discussed. The proposed eight‐antenna MIMO array is formed by integrating four identical building blocks, each of which consists two dual‐mode monopole antenna elements with a neutralization line (NL) embedded in between. Part of the metal frame is exploited to increase the effective resonant length of the monopole antenna. By using the wideband NL, two transmission dips can be generated, and thus an improved isolation (>10 dB) is achieved. The proposed antenna array was simulated and experimentally tested. Good antenna efficiency (>44%) and low envelope correlation coefficient (<0.2) were obtained in the bands of interest. In an 8 × 8 MIMO system with 20 dB signal‐to‐noise ratio, the calculated ergodic channel capacity was as high as 38 bps/Hz in the low band, and 38.3 bps/Hz in the high band. Details of the proposed antenna array are described. The simulated, measured, and calculated results are presented. [ABSTRACT FROM AUTHOR]

In this paper, a compact building block composed of a slot antenna and a loop antenna is proposed. The slot antenna and the loop antenna share a rectangular clearance, which improves the compactness of the building block effectively. Although the slot and the loop have overlapped completely, the proposed building block exhibits good isolation (better than 19 dB) without any external decoupling structure. Four such building blocks are used to implement a compact eight-port multiple-input multiple-output (MIMO) array operating at 3.5 GHz band (3.4–3.6 GHz) for fifth-generation (5G) metal-rimmed smartphone applications. The proposed eight-antenna MIMO array exhibits good isolation of better than 16 dB across the whole operating band. The measured efficiencies of the proposed MIMO array were between 59% and 73%, and its corresponding measured envelope correlation coefficients (ECCs) were better than 0.05. Furthermore, the calculated channel capacity of the proposed MIMO array with 20 dB signal-to-noise ratio (SNR) was about 38.2–39.8 bps/Hz across the desired bands (3.4–3.6 GHz). The measured results confirm that the proposed MIMO array is a good candidate for 5G terminals. [ABSTRACT FROM AUTHOR]

A simple internal antenna design for wireless wide-area network/long-term evolution (LTE) operations is investigated, and it can be incorporated into a mobile phone that has an unbroken metal rim of height 5 mm. The proposed antenna is mainly composed of two parallel slots (dual loop) embedded on the system ground, and by feeding them with an L-shaped coupled feedline with matching networks, good excitation of multiple loop resonant modes can be obtained, which is capable of covering the GSM850/900 (824–960 MHz), DCS/PCS/UMTS2100, and LTE2300/2500 (1710–2690 MHz) operating bands. In addition, the feasibility of realizing decoupled multiantennas ( $2 \times 2$ multi-in multi-out antenna system) is also demonstrated, and its performances are acceptable for smartphone applications. [ABSTRACT FROM PUBLISHER]

The design of a novel practical 28 GHz beam steering phased array antenna for future fifth generation mobile device applications is presented in this communication. The proposed array antenna has 16 cavity-backed slot antenna elements that are implemented via the metallic back casing of the mobile device, in which two eight-element phased arrays are built on the left- and right-side edges of the mobile device. Each eight-element phased array can yield beam steering at broadside and gain of >15 dBi can be achieved at boresight. The measured 10 dB return loss bandwidth of the proposed cavity-backed slot antenna element was approximately 27.5–30 GHz. In addition, the impacts of user’s hand effects are also investigated. [ABSTRACT FROM AUTHOR]

Waveguide structures are criticized for their bulky geometry and heavy weight in practical applications. Therefore, it is necessary to investigate the weight-reduction technique of the waveguide structures, while maintaining their electrical properties and mechanical fabricability. In this paper, a waveguide perforation technique for lightweight purpose is proposed, and an X-band pyramidal horn antenna that employs this technique is developed and tested. To ease the manufacturing process of the 3-D thin-wall structure, a 3-D metal-direct-printing technology is utilized to fabricate the perforated horn. Meanwhile, a full-metal horn without any perforation and a horn printed in dielectric material but coated with metal are also included to compare with the proposed one. Experimental results show that around two-thirds of the total weight can be reduced. Other measured results in terms of electrical performance are in excellent agreement with the full-metal ones, validating the feasibility of the design and fabrication approach. The novelty of this paper realized by the 3-D printing technique is a promising strategy to inspire lightweight structure designs for radio frequency applications. [ABSTRACT FROM AUTHOR]

A single open-slot antenna for long term evolution (LTE)/ wireless wide area network (WWAN) operation is proposed for smartphone applications. To achieve dual-band operation, the narrow open-slot is fed by a simple 50- $\Omega$ vertical feedline with two horizontally protruded feeding structures. To further attain good impedance matching for these two operating bands, an L-shaped metallic plate is used. From the measured results, good antenna efficiencies of more than 40% are demonstrated across the LTE/WWAN operation in the 698–960 MHz and 1710–2690 MHz bands. [ABSTRACT FROM PUBLISHER]