S-Band Compact Microstrip Full-Duplex Tx/Rx Patch Antenna With High Isolation

摘要

In this letter, a new design for two-port transmit/receive (Tx/Rx) full-duplex microstrip patch antenna for 4G and 4G advanced communication systems is introduced. The proposed duplex antenna consists of a single gear-shaped radiating patch for bidirectional radiation. The isolation between transmit and receive ports is achieved by using a frequency space filtering technique where two omega-shaped defected ground structure (DGS)-based bandpass filters (BPFs) are created at transmit and receive ports of the antenna. The antenna achieves a compact size of (70 x 70) mm(2), high isolation larger than -36 dB at the transmit frequency f(t) = 3.3 GHz and larger than -45 dB at the receive frequency f(r) = 3.215 GHz, and small Tx-Rx frequency space ratio r = 0.0245. Also, the proposed structure can cover the entire S-band from 2 to 4 GHz by scaling the sizes of the omega-shaped DGSs to control the resonance frequencies of the embedded BPFs before fabrication. Furthermore, the embedded BPFs have sharp cutoff characteristics, high selectivity, and channel bandwidth of about BW <= 790 MHz at |s11 | = |s22| = -10 dB. The simulation and measurement results highly coincide.