Differentially fed CP antenna with quasi‐self‐complementary semicircular‐ring structure

Abstract

This article presents a new design of a common‐mode suppressed differentially fed circularly polarized (CP) antenna using a quasi‐self‐complementary (QSC) structure. The antenna radiating element consists of a semicircular‐ring radiating patch and its complementary radiating slot counterpart. The design idea for producing CP radiation is based on field orthogonality of the QSC structure. For better impedance matching, a fan‐shaped notch (stub) around the feeding position was cut from (implemented in) the semicircular radiating patch (slot). In addition, to improve the axial ratio, a QSC semielliptical structure is embedded in the central area of the antenna. For the designed differentially fed CP antenna, measurement shows that the differential‐mode (DM) operating band with return loss >10 dB covers 4.76‐6.38 GHz. The measured DM 3‐dB axial‐ratio band is 4.95‐5.43 GHz. Also, very good common‐mode (CM) suppression is observed with the measured CM reflection coefficient >−1.21 dB in 4.50‐6.5 GHz.

Differentially fed dual‐band circularly polarized printed slot antenna with high common‐mode rejection

“…Researchers have also presented many single‐ended dual‐band CP antennas of different structures 2‐9 . Although differentially fed single‐band CP antennas, (such as, the substrate‐integrated waveguide‐fed cavity‐backed aperture antenna in Reference 10, the cross‐dipole antenna in Reference 11, the printed slot antennas [PSAs] in References 12, 13, and the quasi‐self‐complementary antenna in Reference 14) have also been proposed, they are relatively scant. Furthermore, differentially fed dual‐band CP antennas are even scarcer in the literature, with only a few works implemented using microstrip patch, 15 loop, 16 and dielectric resonator 17 structures.…”

Wideband Polarization Reconfigurable Differential Circularly Polarized Antenna

“…Furthermore, balanced systems provide high immunity to environmental noise and electromagnetic interaction between circuit nodes [27]. Differential antennas can be directly connected to balanced circuits to transmit differential signals without the need for baluns [28].…”