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A novel technique for the bandwidth enhancement of conventional rectangular microstrip antenna is proposed in this paper. When a high permittivity dielectric resonator of suitable resonant frequency was loaded over the patch, the % bandwidth of the antenna was increased by more than five times without much affecting its gain and radiation performance. A much more improved bandwidth was obtained when the dielectric resonator was placed on the feedline. Experimental study shows a 2:1 VSWR bandwidth of more than 10% and excellent cross polarization performance with increased pass band and radiation coverage almost the same as that of rectangular microstrip antenna. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 327–330, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10597 [ABSTRACT FROM AUTHOR]

This paper presents the characteristics of a new wideband printed microstrip antenna. This antenna is designed to operate in the C-band, with an impedance bandwidth of about 35% around 5 GHz for a standing-wave ratio (SWR) less than 2. The antenna consists of a probe-fed segmented patch. A narrow slit is made in the patch around the feed region. Design parameters and results are presented. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 11–14, 2002. [ABSTRACT FROM AUTHOR]

This paper presents a novel fully analytical model describing the high-frequency behavior of p-i-n photodiodes. The transport equations are solved, taking into account the dependence of the carrier velocities on the electric field, while the RC-product effect is considered by adding the displacement current in the current equations. The model yields a fully analytical expression for both the bandwidth and quantum efficiency as a function of electrical and geometrical photodiode parameters, as well as material properties. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 329–333, 2001. [ABSTRACT FROM AUTHOR]

The boundary integral method coupled with the segmentation method have been used for the first time to analyze Sierpinski carpet antennas of different orders. As is evident from the close agreement between calculated and measured results for the resonant frequency and input return loss, this technique is found to predict the impedance characteristic accurately. A novel stacked microstrip Sierpinski carpet fractal antenna using a photonic bandgap structure is also presented. Compared to an ordinary microstrip fractal antenna, which has a maximum bandwidth of 2%, the proposed antenna has a higher input impedance bandwidth of about 9%. The radiation patterns of the proposed antenna are improved due to the removal of unwanted radiation caused by the surface wave. The experimental measurement results of the proposed antenna are presented in this paper. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 13–18, 2001. [ABSTRACT FROM AUTHOR]

Wideband T-probe proximity-fed regular circular and compact semicircular patch antennas are proposed in this paper. For the regular circular patch antenna, using a foam layer of thickness ∼0.13λ0 as a supported substrate, an impedance bandwidth of 35% and a gain of over 8.0 dBi have been obtained. For the compact semicircular patch antenna, an impedance bandwidth of 56% and a gain of over 5.4 dBi are achieved with the same substrate thickness. The far-field patterns are stable across the passband. Experimental and computed results based on the finite-difference time-domain method are provided. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 68–71, 2001. [ABSTRACT FROM AUTHOR]

This paper describes a novel planar dual-band inverted-F antenna (PIFA) for which the impedance bandwidth can be remarkably improved. The proposed PIFA uses a single feed only. Two top-plate geometries, an L-shaped and a novel U-shaped slot, are discussed. An example for both slot shapes is given for frequency bands of 2.4 and 5.2 GHz. Simulation based upon the method of moments is used to model the performance of the antennas. Comparisons with measured results on fabricated antenna structures are provided for simulation validation. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 293–298, 2001. [ABSTRACT FROM AUTHOR]

This paper describes a broadband planar rectangular monopole antenna. Both theoretical and experimental investigations have been carried out to draw an analogy between this monopole antenna and a rectangular microstrip antenna. Parametric studies have been carried out to optimize the bandwidth of the planar rectangular monopole antenna. There is good agreement between the theoretical and experimental results. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 55–59, 2001. [ABSTRACT FROM AUTHOR]

In this paper, we present a new topology for a transimpedance amplifier that allows postfabrication bandwidth adjustment by using a control voltage between the ground and the supply level. Simulated results using HEMT and HBT technologies show a significant bandwidth enhancement (25–45%) with a negligible noise penalty. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 47–51, 2000. [ABSTRACT FROM AUTHOR]

This paper describes a new original microwave filter design concept using recursive principles and fully integrable in MMIC technology. To validate this technique, a 7 GHz fixed center frequency filter with 2% bandwidth and a tunable filter with 2.5 GHz tuning range around 8 GHz have been successfully implemented employing a 0.2 μm GaAs P-HEMT monolithic technology. A multicellular approach, using a cascade association of first-order recursive cells, is also described. A tunable two-pole filter has then been realized by a cascade association of two tunable one-pole filters. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 380–385, 2000. [ABSTRACT FROM AUTHOR]

Recently, a new structure called photonic crystals has been receiving much attention. Applications have appeared in the fields of optic, microwaves, and antennas. In this paper, the effect of the variation in the dielectric constant for a two-dimensional photonic crystal is analyzed. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 92–95, 1999. [ABSTRACT FROM AUTHOR]

This paper presents experimental results on a dipole antenna placed inside metallic photonic bandgap materials. Different structures are proposed with single or mixed MPBG configurations. These results demonstrate that a radiated beam can be shaped by appropriately selecting the MPBG. They also show that the antenna bandwidth can be improved by changing the periodicity of the MPBG. These changes must be progressive in order not to disturb the antenna input impedance in the band where it was already working. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 10–16, 1999. [ABSTRACT FROM AUTHOR]

Resonant arrays of waveguide slots suffer from severe bandwidth limitations, which are caused by the frequency dependence of the slot properties, and by the shift in the positions of the standing-wave peaks relative to the slot positions. In this paper, the effects of the use of wideband radiators and subarrays are assessed by means of two representative examples. Results indicate that the potential advantage presented by the utilization of wideband slot radiators is limited, while employing subarraying in the design of planar arrays is the most effective way of improving the bandwidth. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 35–39, 1999. [ABSTRACT FROM AUTHOR]

The performance of a novel multirate subband adaptive beamforming array is evaluated. Instead of the traditional fast Fourier transform (FFT) filter, the quadrature mirror filter (QMF) bank is used here to partition or to subband the incoming signal frequency band. The QMF bank divides the spectrum into the lower and higher subbands. Beamforming is then carried out for both of these subbands. In this paper, the same concept is used, except for the fact that only one of the two subbands (in our case, the lower) is optimized for the desired subband output. This signal is then passed through a multiplier or a transformer, which generates the same output as the other subband (in our case, higher). Both the optimized and transformer outputs are then combined to produce the final signal. This method reduces the circuit complexity as well as the cost of the subband adaptive beamformer. The radiation responses, the mean-square errors, and the eigenspectrums are subjected to investigation. It is observed that the beamforming performance and the mean-square errors (MSE) remain the same for both the previous and novel configurations. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 140–145, 1999. [ABSTRACT FROM AUTHOR]

This paper describes the design and the high performance of a new balanced antipodal Vivaldi antenna for ultra-wideband applications. The return loss, radiation pattern, antenna gain, and level of cross polarization of this antenna are presented for both simulated and experimental results. The antenna is demonstrated to have greater than decade bandwidth (impedance within 10 dB over 1.3–20 GHz) and low cross polarization (<-17 dB in the broadside direction) over the band. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 19: 286–289, 1998. [ABSTRACT FROM AUTHOR]

We have conceived a distributed thermal sensor based on the processing of the correlation function of the thermal noise emitted by the two ports of a small-size lossy transmission line in the microwave domain. The transducer is a lossy coplanar waveguide (LCPW) where losses are created by a thinning down of the central conductor. The two ports of the LCPW are connected to a microwave correlation radiometer. The knowledge of electrical characteristics of the LCPW and an original application of the Kalman filtering to the signals recorded as a function of the delay time of the correlator allow us to retrieve the temperature profile along an LCPW of length 2 cm deposited on alumina. In the present situation, due to a bandwidth limited between 2 and 4 GHz, the spatial resolution of temperature retrieval is about 4 mm. We show in this paper that the application of this processing to the radiometric data obtained with four radiometers of bandwidth 2 GHz, working at 3, 35, 60, and 94 GHz, the spatial resolution, with an LCPW of length 1 mm, becomes 200 μm. These interesting results lead to the definition of a synthetic bandwidth correlation radiometer, and to a demonstration of the feasibility of a new thermometric microsensor. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 19: 94–100, 1998. [ABSTRACT FROM AUTHOR]

Dielectric resonator antenna (DRA) operation at low microwave frequencies has been the subject of much work in recent years. However, the use and characteristics of DRAs at millimeter-wave frequencies have not been explored. DRAs have potential application at millimeter-wave frequencies as there is no conductor loss mechanism in the radiating element. This paper presents the results of an experimental investigation of an aperture-coupled DRA element and array that function in the 40 GHz frequency range. The results presented show that the use of dielectric resonators as antennas can be extended into the millimeter-wave frequencies. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 345–349, 1998. [ABSTRACT FROM AUTHOR]

The profile of fiber Bragg gratings (FBGs) utilized in fiber grating prism and other wavelength-selective phased-array beamformers can be optimized using the results of window theory. In this paper, the window formalism is adopted to quantify the relationship between the FBG profile and its spectral selectivity. It is shown how application of optimum and suboptimum windows affects the reflectivity, bandwidth, and sidelobe level of FBG. Also, the impact of taper on the group-delay nonuniformity, an essential issue for true time delay processors, is discussed. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 161–164, 1998. [ABSTRACT FROM AUTHOR]

In this paper a rigorous theoretical analysis of H-plane waveguide Y-junction circulators with partial-height ferrite post and metallic matching disk is presented. By using the field matching method, various modes in the ferrite post are calculated, identified, and discussed in detail. A series of curves, data, and conclusions which are very useful for the design of practical circulators are obtained. Experimental results are in good agreement with theoretical results. [ABSTRACT FROM AUTHOR]

At present the preferred single stage branchline coupler is the conventional quarter wavelength branchline device. This paper illustrates that the quarter wavelength branchline coupler is a special case of a more general form that allows an infinite range of single stage branchline couplers to be developed for any decree of coupling and for any chosen center frequency. We term these couplers fractional wavelength branchline couplers. It is shown that the characteristics of the fractional wavelength branchline coupler are dependent on the design constraints imposed. The design can be constrained either by choice of branch lengths or by selection of line characteristic impedance. For comparison theoretical and experimental results for bandwidth, coupling, and isolation are shown for an example operating at 10 GHz. [ABSTRACT FROM AUTHOR]

Dedicated Short Range Communications (DSRC) is the key enabling technology for the present and future vehicular communication for various applications, such as safety improvement and traffic jam mitigation.This paper describes the development of a microstrip antenna array for the roadside equipment of a DSRC system, whose characteristics are according with the vehicular communications standards. The proposed antenna, with circular polarization, has a wide bandwidth, enough to cover the current European DSRC 5.8 GHz band and the future 5.9 GHz band for next generation DSRC communications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2794-2796, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26394 [ABSTRACT FROM AUTHOR]

In this paper, design of a compact coplanar-waveguide (CPW) bandpass filter (BPF) for low band (3–5 GHz) of ultra wide band (UWB) application is presented. The filter has design freedoms to obtain the proper bandwidth by tuning the frequencies of the transmission zeros at the passband edge. The equivalent circuit of the filter is also obtained. The designed filter exhibits a good lower stopband with rejection greater than 20 dB below 2.95 GHz, which can block the interference of other wireless communication system below 3 GHz. The designed CPW-BPF is investigated numerically and experimentally. Measured results show a good agreement with the simulated analysis. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 298–300, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24028 [ABSTRACT FROM AUTHOR]

A low power consumption and high gain ultra-wide-band (UWB) low noise amplifier (LNA) utilizing a common-gate stage connected with a common-source stage by using current-reused structure is proposed. The implemented LNA exhibits a maximum power gain of 14.2 dB with a total (core) power consumption of 7.2 mW (3.8 mW) under a 1.5 V power supply. A minimum noise figure of 4.1 dB was obtained within 3-dB bandwidth of 2.7–8.2 GHz. The proposed UWB LNA presents the highest ratio of the power gain to power consumption among the compared papers. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 382–384, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24047 [ABSTRACT FROM AUTHOR]

This paper presents a new CPW-fed monopole antenna, which is composed of two stacked circles with different radii. This novel structure reduces the dimension and improves the impedance bandwidth dramatically. The measured bandwidth defined by VSWR <2.5 is from 3.15 GHz to 27.5 GHz, i.e., a ratio of about 8.7:1. This proposed monopole exhibits a nearly omni-directional radiation pattern with very compact size and simple structure, which is suitable for various military and commercial wideband applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49:1192–1194, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22377 [ABSTRACT FROM AUTHOR]

This paper presents a novel design of the printed hyperpolar-transformed Sierpinski carpet (HSC) antenna. The design parameter and performance of the proposed monopole antenna are investigated and show that HSC geometry gives more freedom for wideband antenna design such as flare angle, scale factor, iteration number, etc. The simulated and measured results are well agreed and we can get octave bandwidth matching performance. The measured results of the return loss, radiation pattern, and antenna gain are also given. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1090–1092, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22361 [ABSTRACT FROM AUTHOR]

In this paper, a compact three-poles hairpin line wideband bandpass filter with several embedded open stubs to improve the stopband is designed and implemented on print circuit board substrate. This filter at center frequency f0 of 4.25 GHz has presented almost very good measured characteristics, including the bandwidth of 3.1–5.4 GHz (3-dB fractional bandwidth of 54%), low insertion loss of -0.7 ± 0.4 dB, sharp rejection due to two transmission zeros in the passband edge created by interstage coupling, and wide stopband rejection greater than 15 dB from 5.6 to 11 GHz. Experimental results of the fabricated filter show a good agreement with the predict results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 934–936, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22302 [ABSTRACT FROM AUTHOR]

In this paper, a compact pseudo-interdigital ultra-wideband filter using several open stubs to improve the stopband is designed and implemented on FR4 substrate. This filter at center frequency f0 of 4 GHz has presented almost very good measured characteristics, including the bandwidth of 3–5.1 GHz (3-dB fractional bandwidth of 52%), low insertion loss of -0.6 ± 0.4 dB, sharp rejection due to two transmission zeros in the passband edge created by inter-stage coupling, and wide stopband rejection greater than 15 dB from 5.3–9 GHz. Experimental results of the fabricated filter show a good agreement with the predict results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 573–575, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22212 [ABSTRACT FROM AUTHOR]

The paper presents a complex global optimization of a four-band planar antenna on an electromagnetic bandgap substrate. As a typical representative of such antennas, a triple U-slot patch antenna is chosen. The full-wave model of the antenna is developed in CST Microwave Studio. Simulation results are exported to macros in Visual Basic, and the structure is optimized by the particle swarm algorithm, which simultaneously changes parameters of the substrate and the layout. As an optimization criterion, impedance matching in the GSM bands and the Bluetooth one is considered. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2532–2534, 2006; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.22006 [ABSTRACT FROM AUTHOR]

In this paper, a clover-shaped microstrip patch antenna for application under an Ultra-Wide Band (3.1–10.6 GHz) is designed and fabricated. To obtain sufficient bandwidth when the Return Loss is < -10 dB, a partial ground plane and coaxial probe source is used. The measured bandwidth of the fabricated antenna is 8.25 GHz when VSWR <2. Referenced to the center frequency, the gain is 3.20–4.00 dBi. The experimental 3-dB beam width (HPBW) in the azimuth and elevation are 55.35° and 62.27°, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2111–2113, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21869 [ABSTRACT FROM AUTHOR]

In this paper, a modified microstrip-fed dipole antenna is presented to improve the stability of the radiation patterns and increase the usable bandwidth. The proposed antenna consists of two parallel dipoles of different lengths to obtain two main resonances. The antenna produces almost similar radiation patterns around the two resonances, and as a result, high pattern stability is realized. The presented antenna provides a wide impedance bandwidth of 90%. In addition, it provides endfire radiation patterns with high gain, low cross-polarization level, and wide beamwidth, which make this antenna a very good candidate for phased arrays and spatial power combiners. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1492–1494, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21740 [ABSTRACT FROM AUTHOR]

A modified microstrip-fed planar monopole antenna with an open-circuited coupled line is presented in this paper. The operational bandwidth of the proposed antenna covers the 2.4-GHz ISM band (2.42–2.48 GHz) and the 5-GHz WLAN band (5–6 GHz). The radiating elements occupy a small area of 23 × 8 mm2. The finite-difference time-domain (FDTD) method is used to predict the input impedance of the antenna. The calculated return loss shows very good agreement with the measured data. Reasonable antenna gain is observed across the operating band. The measured radiation patterns are similar to those of a simple monopole antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1401–1403, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21636 [ABSTRACT FROM AUTHOR]

This paper presents the characteristics of the miniaturized Z-shaped meander-type antenna realized for 5.25-GHz wireless LAN systems. The proposed antenna consists of the modified meander line, corrugated shape, and shorting pin with coaxial feeding on the two-layered (air and FR4) substrate, which forms the letter “Z.” This proposed antenna has equivalent performance with about 44.87% of size reduction with respect to conventional antennas. Its maximum measured impedance bandwidth (-10-dB below) is approximately 300 MHz (5.05–5.35 GHz) or 5.76%, which meets to the bandwidth requirement of WLAN (5.15–5.35 GHz) systems. Details of the proposed antenna are described and experimental results of constructed prototypes also are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1269–1271, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21673 [ABSTRACT FROM AUTHOR]

In this paper, a weathercock-shaped microstrip patch antenna for application in a Hiper-LAN is designed and fabricated. To obtain sufficient bandwidth when VSWR < 2, the T-slot is inserted in the patch and a coaxial-probe source is used. The measured result of the fabricated antenna is 350 MHz or about 7.62% bandwidth when VSWR < 2, referenced to the center frequency, with gain of 5.25–6.70 dBi. The experimental 3-dB beam width is seen to be broad across the passband for the azimuth and the elevation at 80.32° and 83.88°, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 911–913, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21516 [ABSTRACT FROM AUTHOR]

Most reflectarrays use a half-wavelength cell size. In this paper, we present a new reflector-antenna configuration that provides beam scanning and gain improvements by reducing the size of the cells. Small reflectarrays with cell sizes λ/2 and λ/4, respectively, have been designed at 94 GHz. The measured λ/4 reflectarray at 94 GHz achieves a beam scanning angle of ±60° with a loss of gain of 1 dB, whereas the λ/2 one exhibits a loss of 3 dB. Numerical simulations show that the improvement does not appear significant below the limit of λ/6. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 966–968, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21534 [ABSTRACT FROM AUTHOR]

This paper describes a complete low-cost radiating structure, combining a stacked wire-patch GSM antenna, with an active GPS printed element located on the top of the GSM one. The GPS active amplifier and filter are located under the ground plane of GSM antenna and receive the DC bias voltage through the GPS coaxial probe feed. GSM antenna is a low-profile, large-bandwidth antenna with a dipolar radiation pattern. This structure, totally protected by a low-cost dielectric radome, is very suitable for automobile applications needing a very small ground plane. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 970–972, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21536. [ABSTRACT FROM AUTHOR]

This paper presents a wideband patch antenna fed by a modified L probe. The antenna has impedance bandwidth of 21% (SWR < 2) and cross polarization level of less than -15 dB across the operating bandwidth. The antenna has a gain of 8.5 dBi. Both simulated and experimental results are provided, and they are in good agreement. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 977–979, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21538. [ABSTRACT FROM AUTHOR]

A novel parallel-coupled bandpass filter (PC-BPF) with a fundamental frequency of 2.4 GHz is presented in this paper. This proposed filter achieves a broad rejection bandwidth and a sufficient attenuation level by using the distributed interdigital fingers to attenuate the spurious even harmonics of 2f0 and 4f0, and employing a defected ground structure (DGS) resonator to suppress the 3f0 spurious response. The measured results show a satisfactory rejection bandwidth of 8.6 GHz with a rejection level of -30 dB at 2f0. The improved performance will be very attractive for application in many communication systems. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 705–707, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21449 [ABSTRACT FROM AUTHOR]

In this paper, an ultra-broadband patch antenna using a wedge-shaped air dielectric substrate is introduced. By adjusting the angle α, the experimental ratio bandwidth of S11 &les; -10 dB reaches 8.8:1, covering frequencies from 3.05 to 26.87 GHz. The measured impedance locus and radiation patterns at f = 6 GHz and at f = 18 GHz both are presented, and they show broadband characteristics and stability across the whole operating frequency bands, respectively. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 218–220, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21310 [ABSTRACT FROM AUTHOR]

This paper proposes a compact printed hook-shaped monopole antenna for 2.4/5-GHz WLAN applications. The designed antenna has a compact size with dimensions 26 × 10 × 1 mm3. The impedance bandwidth (VSWR < 2) of the proposed antenna is about 170 MHz (2.32–2.49 GHz) for 2.4-GHz (Bluetooth) bands and 4500 MHz (4.4–8.9 GHz) for the 5-GHz (WLAN) bands. The radiation patterns are nearly omnidirectional, which is similar to typical those of monopole antenna. The maximum measured radiation gains are 1.45 dBi at 2.43 GHz and 3.37 dBi at 5.8 GHz, respectively. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 327–329, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21340 [ABSTRACT FROM AUTHOR]

A novel hemispherical helical antenna is designed for satellite communications in this paper. This antenna can produce circular polarization radiation over a wide angular coverage of 113°. The input impedance varies very stably in the range of 1 < cλ < 1.15. The 3-dB axial-ratio bandwidth is found to be 13.5% with relatively high gain of 9 dB. The current distribution and radiation pattern will also be presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 361–363, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21349 [ABSTRACT FROM AUTHOR]

A parallel coupled-line microstrip filter is designed and implemented on PCB with its maximum bandwidth. In this paper, this filter has presented almost very good characteristics including the simulated bandwidth of 67%, the measured bandwidth of 64%, lower insertion loss of 1.27 dB, and flat response in the pass-band. The maximum bandwidth fabricated on PCB shows good agreement with the theoretically calculated bandwidth of 70% due to the narrower gap size between the coupled lines. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 373–375, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21353 [ABSTRACT FROM AUTHOR]

This paper presents two designs of square-ring slot antennas to suppress the 2nd and 3rd harmonics by involving a frequency-selective surface (FSS) with square-loop-type and meandered-dipole-type elements. The transparency of the surface in the higher-order mode makes the ground plane invalid, so that the harmonics cannot resonate and emit. The experimental results show that the FSS structure not only demonstrates band-reject characteristics, but also well retains the antenna performances for fundamental-mode operation. Moreover, with the square-loop-type lattice, the impedance bandwidth was increased by about four times as much as that of the reference antenna. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 47–49, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21256 [ABSTRACT FROM AUTHOR]

In this paper, a novel balanced T-shaped printed antenna is proposed for 3G IMT2000 mobile handsets for the WLAN (IEEE802.11b) module. This balanced T-shaped antenna is designed for microstrip-feeding with balanced signals. The antenna was designed by merging an unbalanced T-shaped antenna and a planar balun. A prototype of the antenna for operation at the IMT2000/IEEE802.11b bands is constructed and described. The measured and simulated return loss (in terms of the mixed-mode S-parameters) and measured radiation patterns are obtained. The experimental results demonstrate the broad bandwidth and omnidirectional radiation performance of the newly developed antenna. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 131–133, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21285 [ABSTRACT FROM AUTHOR]

This paper presents a new coplanar waveguide (CPW) orthogonal feed with T-match that is used to excite a dielectric resonator antenna (DRA). It results in a compact and highly efficient radiating element appropriate for active arrays. The simulated and measured results are presented at 5 GHz, which exhibit a large bandwidth. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 530–532, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21038 [ABSTRACT FROM AUTHOR]

A diamond dipole antenna (DIDA) with rounded feeding edges for ultra-wideband (UWB) communications, optimized using the finite-difference time-domain (FDTD) technique is presented in this paper. The antenna has a bandwidth of 11.15 GHz (5.34:1) for a voltage standing wave ratio (VSWR) ≤ 2, while retaining good radiation pattern characteristics in this bandwidth. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 536–538, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21040 [ABSTRACT FROM AUTHOR]

This paper presents design simulation, implementation, and measurement of a miniature GPS/K-PCS dual-band LTCC chip antenna for mobile-communication handsets. The dimensions of the LTCC chip antenna are 9 × 15 × 1.2 mm. The lower meander-type antenna is tuned to the lower-frequency (GPS) band and the upper meander antenna with via-hole connection contributes to the higher-frequency (K-PCS) band. In order to lower the resonant frequency for the GPS band, a printed modified meander antenna with gap stub is used for integration with K-PCS band operation. The measured impedance bandwidths (VSWR ≤ 2) are 55 and 120 MHz at the resonant frequency, respectively. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 431–433, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21007 [ABSTRACT FROM AUTHOR]

A novel compact shorted patch antenna with the bowtie-type patch and the dual triangle portion to obtain a large bandwidth (790–970 MHz) is presented in this paper. Using shorted patches with via holes, a size reduction of 95.7% is achieved, as compared to that of the conventional half-wave patch antenna. Moreover, it has 10-dB return-loss bandwidth of 20.4% for the GSM and CDMA bands. This proposed antenna exhibits not only a compact and a thin profile, but also wideband characteristics. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 4–6, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20884 [ABSTRACT FROM AUTHOR]

This paper presents a novel square-cylindrical monopole antenna fabricated using a single metal plate. A prototype of the proposed antenna with a cross-sectional area of 10 × 10 mm2 and a length of 30 mm is implemented, and the measured results indicate that the antenna can provide good omnidirectional radiation over a wide frequency band covering 2 to 11 GHz, thus making it very promising for IEEE 802.16a operation. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 419–421, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20841 [ABSTRACT FROM AUTHOR]

This paper presents a new technique to improve the impedance bandwidth of a rectangular planar monopole. The method involves beveling one part while keeping the other edges near the ground plane, which is connected to the antenna-feeding port. The measured impedance bandwidth of the monopole can reach a ratio of 14:1 for a voltage standing wave ratio (VSWR) equal to 2:1. The measured radiation patterns of the antenna retain the typical monopole characteristics throughout the bandwidth. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 124–126, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20744 [ABSTRACT FROM AUTHOR]

In this paper, two L-shaped slots are introduced in order to obtain triple-band operation with a planar monopole antenna fed by a 50Ω coplanar waveguide (CPW) transmission line. Prototypes of the proposed antenna with sufficient bandwidths in the 0.9-, 1.8-, and 2.15-GHz bands for GSM, DCS/PCS, and IMT-2000 systems, respectively, have been constructed and tested. Details of the experimental results are presented and discussed. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 510–512, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20682 [ABSTRACT FROM AUTHOR]

In this paper, an approach for bandwidth enhancement of a small-sized harmonic-suppressed antenna is presented. For bandwidth enhancement and miniaturization of the harmonically suppressed slot antenna, a bowtie-shaped meander slot antenna is proposed and demonstrated experimentally. From the measured results, the proposed antenna has a wideband characteristic with a harmonic-suppression characteristic at the 2nd and 3rd frequencies. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 585–587, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20703 [ABSTRACT FROM AUTHOR]