Dual‐band full‐duplex antenna with high isolation using differential fed and dual‐polarization

Abstract

This study proposes a new design approach for a dual‐band full‐duplex antenna to achieve high interport isolation using the differential fed technique. It consists of a single radiating patch, a differential fedline, and a direct fedline. A slotline‐based balun is used in the design to implement the differential fed, which offers minimum phase and magnitude imbalances to the patch of the antenna. The differential fed and direct‐fed lines are orthogonally connected to the radiating patch to realize dual polarization. Both the dual‐polarization and differential fed techniques help to improve the interport isolation of the antenna. It offers an interport isolation of more than 51 and 53 dB over the entire lower and higher operating bands, resonating at 3.22 and 4.1 GHz with 84 and 110 MHz bandwidths. To validate the proposed antenna, a prototype has been fabricated on an FR‐4 substrate with the dimensions of (1.79 × 1.79 × 0.017)λg (λg is the guided wavelength in the substrate at the lower frequency f1), with measured results consistent well with simulations. The far‐field measurement exhibits that the proposed antenna provides a unidirectional broadside radiation pattern and achieves a minimum cross‐polarization of less than −38 dB in all directions and less than −42 dB in the direction of the main lobe in both E‐ and H‐planes at the resonant frequencies. The antenna has insignificant backward radiation with the front‐to‐back ratio bold-italic≥ ${\boldsymbol{\ge }}$20 dB when port1 is active and the front‐to‐back ratio bold-italic≥ ${\boldsymbol{\ge }}$30 dB when port2 is active. Moreover, the proposed antenna design is simple and easy to fabricate as the differential fed is implemented using the slotline‐based balun within the same general purpose FR‐4 substrate layer. This eliminates the need for any additional and separate circuits for differential fed and minimizes the overall volume of the antenna.

A self‐quadruplexing antenna for quad‐band wireless applications

“…The keysight advanced design system (ADS) is utilized to simulate the equivalent circuit model for the validation of the simulated results of the proposed design. The model represented an electrical circuit, which is a simplified and equivalent version reported in Prasad et al 22 The model employed a parallel RLC circuit to represent a single‐band resonator. The concept has been extended to the remaining ports of the resonator.…”

Compact and Highly Isolated Continuous Scanning Dual-Polarized Holographic Antenna Using a Pillbox Feeding Structure

“…In addition, in the case of the array system, each feeding element necessitates a large space, thereby increasing system size [13]. To overcome these drawbacks, a previous study used a pillbox feeding structure in a single-polarization HA to minimize the size of the feeding structure, reducing the overall antenna size [14,15]. However, the conventional pillbox feeding structure is only designed for singlepolarized HAs, rendering it difficult to support dual-polarized HAs [14].…”