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A triband monopole patch antenna with high figure-of-merit (FoM) for WiMAX and WLAN applications has been proposed. It consists of a rectangular patch with two asymmetrical L-shaped slots, where L-slots generate two lower resonance frequencies and patch the higher. A parametric study to optimize the slot length is carried out to achieve the desired frequency bands. An equivalent circuit model of the antenna is developed and analyzed for loss due to input impedance mismatch at each resonance frequency. The simulated results of return loss of antenna and radiation patterns are validated with experimental results. © 2017 Wiley Periodicals, Inc.

In this article, a cylindrical dielectric resonator antenna (CDRA) excited by a 45° rotated square ring slot with a T-shaped coupling microstrip line is investigated for circularly polarized (CP) operation. The proposed antenna shows the dual band characteristics and the lower band is generated due to T-Shaped microstrip line and upper band is due to CDRA. In the proposed antenna, the two degenerate broadside orthogonal modes ( HE11δx mode and HE11δy mode) of the CDRA are used to realize CP radiation. The prototype of the proposed antenna has been fabricated and tested. The measured |S11| bandwidth in the lower and upper band is found to be 14.65 and 19.86%, respectively. The measured 3-dB axial ratio bandwidth of 1.46 and 6.01% is achieved in the upper band only. Proposed antenna has been found suitable for wireless application.

In this article, compact quad-band cylindrical dielectric resonator antenna (CDRA) with complementary C-shaped defected ground structure (DGS) is examined. The proposed antenna design is excited by annular shape microstrip line. Annular shape microstrip line, at center position and shifted from center position, are used to generate HE12δ and HE11δ mode in CDRA at 12.1 GHz and 11.6 GHz, respectively. Complementary C-shaped DGS is used to make proposed antenna design compact (approximately half the resonant frequency of CDRA mode). Archetype of antenna structure has been fabricated and experimentally tested. The proposed antenna operates in four frequency bands 3.21–3.63 GHz; 4.83–6.78 GHz; 7.25–7.77 GHz, and 11.76–12.45 GHz with a fractional bandwidth of 14.36%, 23.14%, 3.68%, and 1.88%, respectively. The proposed antenna design is applicable for WLAN (5.2/5.8 GHz) and WiMAX (3.5/5.5 GHz) bands. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:611–615, 2016

In this work; the novel design of dumbbell shaped frequency selective surface (FSS) is demonstrated as superstrate. The array of this designed FSS structure is incorporated on two different antennas; (1) Microstrip Patch Antenna (MPA), and (2) Inverted Stacked Microstrip Patch Antenna (ISMPA). The FSS unit cell reflection magnitude is nearly 0.95 in the vicinity of both antennas resonance frequencies. Based on the ray tracing phenomenon multiple reflections occur between superstate and ground plane. So by this phenomenon the gain of circular patch and the ISMPA is enhanced by 6.02 dBic and 5.1 dBic respectively. In the measured results, the impedance bandwidth of MPA and ISMPA are 6.66% (5.8–6.2 GHz) at 6 GHz center frequency and 5.3% (5.53–5.83 GHz) at 5.67 GHz center frequency respectively. The corner truncated dumbbell shaped FSS layer also acts as a polarizer. The axial ratio 3 dB band width of MPA and ISMPA are 8.66% (5.64–6.16 GHz) and 12.6% (5.52–6.24 GHz). Here simulation results are shown good agreement with measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:732–740, 2016

In this letter, a triple band two-segment cylindrical dielectric resonator antenna with a partial ground plane is investigated. Proposed antenna is excited by a novel microstrip feed that having a microstrip line along with two ring patches. Proposed triple band antenna has been analyzed, studied, and optimized using Ansoft HFSS simulation software. Prototype of proposed structure has been fabricated and tested. Good agreement has been obtained between simulated and measured parameters. The proposed design operates in three different frequency bands, that is, 2.3–2.5 GHz; 3.2–3.8 GHz; 4.67–7.0 GHz with the fractional bandwidth of 8.33%; 17.14%, and 39.93%, respectively. Proposed antenna is able to cover three frequency bands for different wireless applications (WLAN [2.4/5.2/5.8 GHz] and WiMAX [3.5/5.5 GHz] bands). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2649–2655, 2015