In this paper, a circularly polarized (CP), high gain and wide bandwidth metal plated microstrip antenna (MSA) using partially reflecting surface (PRS) and artificial magnetic conductor (AMC) layers is proposed. The bandwidth of MSA is increased primarily, using AMC layers, and gain is increased by placing the antenna in a Fabry-Perot cavity (FPC) resonator. The two slotted AMCs are designed to resonate at two frequencies which electromagnetically couple to provide wide bandwidth. The FPC antenna with PRS and AMC layers provides higher gain, more impedance bandwidth, less gain variation and more miniaturization than the antenna without AMC layers. The proposed antenna provides S 11 < −10 dB, axial ratio (AR) < 3 dB and 17.4 dBi peak gain with gain variation < 3 dB over 5.725 GHz to 6.4 GHz frequency band. Broadside radiation patterns have side lobe level (SLL) < −20 dB, cross polarization (CPL) < −16 dB and front to back (F/B) lobe ratio > 20 dB. The overall antenna dimensions are 2.83λ 0 × 3.23λ 0 × 0.49λ 0 , where λ 0 is the free space wavelength corresponding to the central frequency of 5.725-6.4 GHz. The proposed structure is fabricated, and the measured results agree with simulation ones.

No abstract

No abstract

This paper proposes low profile, high gain and wideband circularly polarized (CP) microstrip antennas (MSA), using gap coupled parasitic patches (PPs) on superstrate layer. Printed and suspended probe fed, CP MSAs are designed on a 1.59 mm thick FR4 substrate, and an array of closely spaced hexagonal PPs are printed on the bottom side of the 1.59 mm thick FR4 superstrate and placed at a height about λ 0 /8 above the ground plane, where λ 0 is the free space wavelength, corresponding to the central frequency of the operating frequency band. The gap coupled hexagonal PPs are not only used to enhance the axial ratio bandwidth (AR BW) and gain of the antenna, but also used to reduce impedance and gain variation of the antenna over the operating frequency band. 'Ant9' is a suspended MSA with 7 hexagonal PPs. A prototype 'Ant9' is fabricated and tested, which provides a peak gain of 9 dBi, S 11 < −10 dB, gain variation < 1 dB, and AR < 3 dB over 4.9 to 6.45 GHz frequency band. ARBW of 27.3% is achieved. The proposed 'Ant9' covers three frequency bands viz., 5.15 to 5.35 GHz, WLAN band, 5.725 to 5.875 GHz, ISM band, and 5.9 to 6.4 GHz, Satellite C band. The space fed antenna configuration reduces the cross polar radiation level (CPL) and increases the efficiency of the antenna. The measured results agree with the simulation ones. The overall size of 'Ant9' is 0.96λ 0 × 0.96λ 0 × 0.136λ 0 .

In this paper, a quarter circular sector with an inverted L shaped monopole antenna for tri-band applications is proposed. The antenna is designed from a U shaped ultra-wideband (UWB) antenna. The number of higher-order modes, each with wide bandwidth, gets excited in a monopole, which electromagnetically couple to provide UWB. In the proposed tri-band antenna the electromagnetic coupling between higher-order modes is reduced by selectively removing the symmetrical portion and decreasing the thickness of the UWB radiator. An inverted L strip is added to a quarter circular sector, and a similarly shaped parasitic element is placed close to the radiator to achieve the desired tri-band. The antenna provides S 11 ≤ −10 dB over 2.1-2.5 GHz, 5.0-5.6 GHz and 8.4-9.0 GHz which covers 3G, Wi-Fi, LTE, Bluetooth, WLAN, and X-band applications. The antenna offers nearly omnidirectional radiation pattern in the lower band and directional radiation pattern in the other two bands. The prototype antenna is fabricated on a 0.147λ 0 × 0.22λ 0 FR4 substrate, where λ 0 is the free-space wavelength corresponding to 2.1 GHz. The measured results agree with simulation ones.