Differential-Fed Log-Periodic Dipole Array With High Isolation for Wideband Full-Duplex Communications

Abstract

This study presents a differentially driven log-periodic dipole array system with high isolation between reception and transmission ports for wideband full-duplex applications. The antenna system is composed of two pairs of log-periodic dipole arrays operating in the X-band spectrum from 8 GHz to 12 GHz. The system offers a low cross-polarization between E-plane and H-plane (less than −25 dB). The simulation results show high isolation S 21 < −60 dB through the entire X-band while the measured results reach S 21 < −45 dB in a reflective lab room. Furthermore, in order to verify the measured values, a modified 180 • out-of-phase wideband power divider is used to feed transmitting and receiving ports. The second measured outcomes also attain total isolation greater than 45 dB for the entire band of interest. The proposed design is able to cover both orthogonal transmitted and received directions with reasonable gain values, high efficiency, and good impedance matching.

A High Performance Duplexer Based on Dual-mode E-type Resonator

“…I n wireless communication system, the duplexer is one of the key components in selecting channels, synthesizing signals, and separating frequencies. In recent years, it has been increasingly used in modern high-speed wireless systems such as GSM, CDMA, and UMTS-WCDMA [1][2][3][4][5][6][7].…”