CPW-fed C-shaped slot antenna for broadband circularly polarized radiation

Abstract

A novel broadband circularly polarized (CP) C-shaped slot antenna fed by a coplanar waveguide is presented. The broadband CP operation can be achieved simply using a C-shaped slot in the ground to produce orthogonal surface currents for left-hand circular polarization. Using the semicircle-shaped radiator patch, wide impedance bandwidth and broad axial-ratio (AR) bandwidth can be obtained simultaneously. The measured results show that the proposed antenna can provide a 10-dB impedance bandwidth of 105% from 2.78 to 8.92 GHz, and a 3-dB AR bandwidth of 70.4% from 2.9 to 6.05 GHz. Finally, an antenna prototype with a reflector for unidirectional pattern applications is also developed. The proposed antenna has broader impedance and CP bandwidths but with a more compact size compared with the previous designs. V C 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:739-746, 2015.

Balanced circularly polarized square loop antenna under even-mode resonance

“…Now, let's further give comprehensive comparison with other typical uni-directional CP antennas in terms of the beam directions, front-to-back ratio, gain and 3 dB-AR beamwidth as Table 3. It is seen that the proposed antenna exhibits an axial-mode CP beam, and it is distinctive from most of the loop-like and slot-like antennas 22,[24][25][26][30][31][32][33][34]46,47 having normal-mode radiation patterns. The proposed CP antenna has simultaneously exhibited a wide 3dB AR beamwidth of 708, and a front-to-back ratio of 40 dB when using a planar reflector.…”

“…In general, the operation principle of most loop‐like CP antennas is to simultaneously excite the 2 orthogonal linearly polarized (LP) modes with equal amplitude and in quadrature‐phase with by various perturbations. When such antennas are cavity‐backed and designed as uni‐directional antennas, it is found that the front‐to‐back ratio is <20 dB . Meanwhile, most of these antennas still exhibit relatively complicated structures with many design parameters .…”

“…When such antennas are cavity-backed and designed as uni-directional antennas, it is found that the front-to-back ratio is <20 dB. 22,[30][31][32][33] Meanwhile, most of these antennas still exhibit relatively complicated structures with many design parameters. [30][31][32]34 Therefore, it is a challenging task to design a loop-like CP antenna with a high front-to-back ratio while maintaining a relatively simple loop-like structure.…”

A compact broadband coplanar waveguide fed circularly polarized printed monopole antenna with asymmetric modified ground plane

“…Several printed CP monopole antennas with different shapes and techniques were proposed in References . Examples include using a branched microstrip feed line with parallel slots, C‐shaped slot antenna, moon‐shaped patch and moon‐shaped ground plane, and parasitic patches with an L‐shaped slot . Although all of these previous designs have a wide ARBW, they have a large size.…”

“…Examples include using a branched microstrip feed line with parallel slots, C‐shaped slot antenna, moon‐shaped patch and moon‐shaped ground plane, and parasitic patches with an L‐shaped slot . Although all of these previous designs have a wide ARBW, they have a large size. To reduce the antenna size while retaining a wide IBW and ARBW, two antenna designs were proposed in References .…”