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This article introduces analysis of the new configuration; inductor loaded left‐handed composite right‐/left‐handed transmission line ((L‐CRLH TL). Compared to conventional CRLH and dual CRLH, this configuration has the advantage of very slow phase (almost constant) and nonlinear propagation coefficient which enables it to be very effective in designing compact size and ultra‐wideband (UWB) microwave components. The theoretical and circuit model of the L‐CRLH TL is discussed. As an application, a compact UWB (3.1‐10.6 GHz) L‐CRLH power divider is designed using only one L‐CRLH cell with size of 2.7 × 8.6 mm2 whereas the whole power divider photoprint is 12.14 × 18.83 mm2. The size is 58.5% smaller compared to the conventional narrow band T‐junction power divider designed at the mid frequency. The results reveal good insertion losses (3.2 ± 0.2 dB for both S21 and S31), and good return losses (better than 10 dB within the passband). [ABSTRACT FROM AUTHOR]

An electrically small antenna ensures easy integration with devices without compromising the form factor. The performance in terms of bandwidth, gain and so on for these antennas is extremely critical and is governed by fundamental limitations in size, i.e. Chu's limit. This study initially presents an analysis of these limits and corresponding performance parameters. Next, a compact dual-band antenna has been designed using an electric field driven LC (ELC) resonator and a coplanar ground plane which operates at GSM 1800 and Wi-MAX. This proposed antenna has a compact size of 0.31λ0 × 0.08λ0 × 0.01λ0 in the first band which is resonant at 1.89 GHz. Finally, a conducting layer is placed below the ELC resonator and both are connected through a via. This provides stronger capacitive coupling between the radiator and the feeding arm and thus, results in miniaturisation of 76.9% in the area. The new antenna is electrically small and covers various cellular bands such as GSM 900, Bluetooth, Wi-Fi and Wi-MAX. Prototypes of both designs have been fabricated and experimentally tested in order to validate the simulation results. [ABSTRACT FROM AUTHOR]

This study introduces a compact asymmetric coplanar strip (ACS)-fed composite right--left-handed (CRLH) multipleinput--multiple-output (MIMO) antenna for multiband operation. The ACS fed MIMO antenna is composed of two elements; each is operating at 5, 5.8 and 6.3 GHz; for different wireless applications. The overall MIMO antenna size is compact (46 x 26 mm²). A unit cell of the CRLH connected to 50 Ω ACS fed is considered the main block of the antenna. The edge-to-edge separation between antenna elements equals 0.4λ0 at 5 GHz. The insertion loss, correlation coefficient, diversity gain and channel capacity are used to evaluate the performance of the ACS-fed MIMO antenna. The isolation higher than 25 dB and envelope correlation lower than 0.05 have been achieved without using any extra decoupling structures. The experimental results are reasonably well agreed with simulated ones. [ABSTRACT FROM AUTHOR]

This paper discusses the properties of hybrid terminated metamaterial CRLH resonant antennas. The antenna proves that the hybrid termination can increase the electrical length of based antennas and hence it can increase the number of possible frequency bands at compact size. This is emphasized through developing a dual band hybrid termination CRLH cell antenna resonating at 2.4 GHz and 5.2 GHz. The antenna design and performance is compared to open/short circuit termination CRLH resonant antennas. All the discussed antennas in this paper have same compact size (21 × 31 mm2). An experimental measurements are carried out for the hybrid terminated CRLH resonant antenna as further validation. The proposed antenna can find possible applications in WiFi/WiMAX services. [ABSTRACT FROM AUTHOR]

This article presents a new small size dual band metamaterial antenna. The antenna is realized using a single cell of a suggested modified version of composite right left handed transmission line terminated by a hybrid capacitive loading with short circuit termination. The hybrid termination leads to decrease the size of the antenna whereas the modified composite right left handed cell configuration leads to introduce dual band antenna functionality at 2.5 and 2.92 GHz. The antenna size is only 31 × 26 mm2. Compared to, single band, non-selective, conventional patch antenna, the size of the proposed antenna is only 9 and 11.5% at the two former frequencies, respectively. Despite the small size, the antenna gain is more than 3.5 dBi at the two operating frequencies. Moreover, the antenna has a high roll off beyond the operating frequency band which leads to high selective characteristics. The antenna can suppress 100% of the nearby signal power beyond its bands by 300 MHz at lower band and 200 MHz at upper band. The antenna design is discussed; the full wave simulation and experimental measurements are introduced for validating the results. [ABSTRACT FROM AUTHOR]

ABSTRACT A compact size and high selective bandpass filter is presented in this paper. The filter is designed to serve at 3.5 GHz with two transmission zeros at 3.35 GHz and 3.85 GHz. The filter is designed as two gap capacitor coupled to two coupled composite right-left handed transmission lines. The coupled lines were designed to demonstrate a zeroth order phase at 3.5 GHz. Also, the transmission zeros were achieved as a consequence of the electrical/magnetic couplings between the two coupled transmission lines. The employed cell, filter design equations are emphasized. The filter S-parameters were extracted based on the circuit model, full wave simulation, and experimental measurements. A good agreement between modeled, simulated, and measured results is achieved. The measured center frequency of the bandpass filter is 3.55 GHz and 100 MHz bandwidth which is suitable for WiMAX applications. Also, the filter has low measured insertion loss which does not exceed 1 dB within passband. Finally, the filter has advantages of compactness (size is 20 × 18 mm2) which is only 50% compared to conventional non-selective one-stage coupled line filter. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1248-1251, 2017 [ABSTRACT FROM AUTHOR]

ABSTRACT This study presents the design of an electrically small metamaterial antenna with dual-band characteristics for WLAN and WiMAX applications with coplanar ground. The proposed antenna consists of stepped-impedance closed ring resonator (SICRR) and a small rectangular patch which is designed by etching a split ring resonator (SRR) from a rectangular patch which is turn fed through main feed. Such metamaterial composite exhibits dual-band behavior with first band operating at 2.45 GHz with an impedance bandwidth (| S11| < −10 dB) of 8.16% while second band is resonant at 3.37 GHz having an impedance bandwidth of 23.74% respectively. The proposed antenna is designed specifically to operate at WLAN (2.5 GHz) and WiMAX (3.5 GHz) and shows compact nature with a radiating element size of 0.16λo × 0.097λo × 0.013λo. Equivalent circuit of proposed antenna has also been modeled which is in good agreement with the antenna behavior. The proposed structure shows end fire radiation pattern in H-plane and omni-directional radiation pattern in E-plane at all operating frequencies with low cross polarization levels. The prototype has been fabricated and experimentally tested to validate the simulation results which are in good agreement with the measured results. The antenna is suitable for use in Bluetooth, WLAN and WiMAX. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:573-578, 2017 [ABSTRACT FROM AUTHOR]

This study presents a hybrid electromagnetic isolation mechanism in a transceiver array antenna operating at 5.8 GHz. Maximum isolation between transmitting and receiving array antennas, at a very close spacing (3 mm = 0.0580), and minimum mutual coupling between each array elements is achieved without antenna radiation pattern degradation. The achieved separation is equivalent to 44% size reduction compared with conventional half wavelength spacing criterion. Each of the transmitting and receiving array antennas is a four-element linear microstrip patch array antenna. The employed hybrid isolation technique is composed of defected ground structure, to minimise coupling between array elements, and uniplanar electromagnetic bandgap, to minimise the coupling between the transmitting and receiving antennas. The resulting transceiver array antenna system fulfils -35 dB mutual coupling between array elements, and 60 dB isolation between opponent transmitting and receiving array antennas. The proposed design procedures are discussed and analysed using electromagnetic full wave simulations. Results were verified through experimental measurements for reflection coefficient, mutual coupling and radiation characteristics in which a good agreement with simulated results is granted. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents a new compact asymmetric coplanar strip -fed UWB MIMO antenna. The UWB MIMO antenna consists of two identical elements which have quarter elliptical ring radiating element with asymmetric coplanar strip-fed. By designing the antenna using asymmetric coplanar strip-fed, the antenna size can be reduced (its size is only 6 × 2.6 cm2). The distance between the two antenna elements equals 0.37 λ0-The single antenna element is operated at frequencies from 3.1 GHz to 10.6 GHz with reflection coefficient lower than −10 dB. In addition, the designed antenna elements have less than 15 dB coupling isolation between the two input ports. The diversity performance between two antenna elements such as envelope correlation coefficient and diversity gain are investigated and they are within their allowed limits. This analysis confirms that the designed antenna is suitable for portable UWB MIMO applications. The proposed antenna is designed; simulated and measured. There is a good agreement between the simulated and measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:31-36, 2017 [ABSTRACT FROM AUTHOR]

The theoretical study and experimental results of a compact tunable left-handed (LH) zeroth order metamaterial ferrite resonator is presented. The resonator has been designed and realised using a LH coplanar waveguide transmission line on a ferrite substrate. The theoretical analysis of the operation principles of the resonator has been provided. The detailed measurement setup and experimental results are discussed. The resonator is only 0.19 λg (65% reduced in size comparing with conventional one) at 4 GHz. The resonator has fractional bandwidth of 0.1% and average insertion loss, approximately 4.5 dB. Moreover, the zeroth order metamaterial ferrite resonator has tuning capability and requires lower DC magnetic bias. [ABSTRACT FROM AUTHOR]

This study presents the design of switching techniques for dual-notched ultra-wideband antenna. The dual bandnotched frequencies are achieved by using switched defected microstrip structure band stop filter inserted in the microstrip feed line and a switched meandered slot etched in the radiation patch. The switching reconfiguration is accomplished by combining the two ideal switches to introduce a notch filter response to prevent the interference to the primary users operating in the middle and upper WiMAX wireless local area network bands. The proposed structure has four modes by controlling the two switches on and off. The proposed antenna has good matched impedance from 2.5 to 12 GHz with two notched bands from 3.3 to 3.8 GHz (middle WiMAX applications) and from 5.1 to 5.9 GHz (upper WiMAX applications). The antenna is fabricated and tested. Good agreement is achieved between the simulated and measured results. [ABSTRACT FROM AUTHOR]

In this study, the authors present a novel compact non-reciprocal ferrite forward composite right-/left-handed (CRLH) coupled-line coupler (CLC). The proposed forward coupler is realised in coplanar waveguide configuration using series air gap capacitors and shunt planar segment inductors. A theoretical coupled mode analysis of a general non-ferrite CRLH forward CLC has been proposed. The mode analysis is then extended to ferrite CRLH forward CLC. The ferrite coupler's performance has been further analysed numerically and verified experimentally. Both numerical and experimental results have shown that the coupler demonstrates non-reciprocal operation for both forward coupling and through propagations. The coupler can achieve ~10 dB forward coupling and through levels with nonreciprocity isolation up to 30 dB. Moreover, the coupler has high backward coupling isolation better than 20 dB and very compact size with coupling length = 0.08 λ0 or (0.2 λg) at 8 GHz which is significantly smaller compared with any forward coupler reported to date in the similar operating frequency bands. Although, a conventional ferrite forward CLC can be non-reciprocal, it has long length, resulting in very high losses. This is not the case for the proposed CRLH coupler. Hence, the novelty and advantage of the coupler are its combined properties in compactness and nonreciprocity. Furthermore, the coupler requires very low external DC magnetic bias because of its much lower demagnetisation compared with the microstrip configuration. [ABSTRACT FROM AUTHOR]

Introduced in this letter is a thin, flexible, compact, and fully fabric I‐shaped quarter‐wavelength antenna, where a 3 × 3 array reflector, is in the antenna rear end. In free space, the I‐shaped antenna radiates at 2.45 GHz of the Industrial, Scientific, and Medical band with simulated realized gain of 1.65 dB and 90% worth of simulated radiation efficiency. The array reflector is utilized to diminish the specific absorption rate (SAR) in human evaluation scenarios. At the operating frequency, in free space, the antenna realized gain is improved by 75% after incorporating the artificial magnetic conductor (AMC) array. Moreover, over 1 g of tissue, a SAR reduction of 99.5% is attained at 2.45 GHz. Simulation and measured S11 and radiation pattern comparisons are highlighted in this letter. Based on the accomplished outcomes, the integrated antenna, comprised of the fully fabric I‐shaped quarter‐wavelength antenna and the AMC array, might be considered for wearable applications. [ABSTRACT FROM AUTHOR]

This study presents, for the first time, a novel π - T generalised negative refractive index (NRI) transmission line (TL) configuration. It is innovated for increasing the possible passbands in designing microwave components. It is proved that the proposed transmission line can introduce up to seven passbands for completely unbalanced transmission line condition. The detailed mathematical analysis of that configuration based on the periodic network analysis and equivalent circuit model is introduced. As an application for the novel π - T generalised NRI TL configuration, a new compact triple band coplanar waveguide (CPW) metamaterial filter is introduced. The proposed triple bands CPW filter design steps are introduced and its performance is validated using equivalent circuit model simulation, electromagnetic full wave simulation and experimental measurements. Good agreements between the circuit modelling, electromagnetic full wave simulation and practical measurement results are achieved. All the results confirm that the proposed filter has triple passbands from 900 to 960 MHz, 1.4 to 1.48 GHz and 2.4 to 2.45 GHz. Moreover the filter size is compact whose length is only 12.1% λg at first passbands, 18.2 λg% at second passbands and 31.7 λg% at third passbands. [ABSTRACT FROM AUTHOR]

A novel ferrite nonreciprocal left-handed (LH) transmission line is presented. The proposed structure is composed of a coplanar waveguide over a ferrite substrate, horizontally magnetized and periodically loaded with only shunt inductors. The line has a nonreciprocal LH propagation with transmission level better than -5 dB with isolation level up to 20 dB over a moderate bandwidth. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2810–2814, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22848 [ABSTRACT FROM AUTHOR]