Dual-Linear Polarized Antenna Module with Enhanced Transmit- Receive Isolation

A dual-linear polarized antenna module for frequency-domain duplex base-station antenna arrays is described. Designed for the frequency bands of 1.92-1.98 GHz and 2.11-2.17 GHz, the antenna radiators are matched to -17dB return loss. The antenna modules have been arranged in a dual-linear polarized array. Inter-element coupling has been reduced by the insertion of conducting walls. The module features separate feeds for transmit (TX) and receive (RX) signals, and realizes a TX-to-RX isolation of 20dB in the described array arrangement. The balanced-fed radiator elements are surface-mount onto a printed circuit board, which serves as a groundplane and provides the balun structures. A radiator is made of a single, three-dimensional part suited for injection molding, allowing for the production of lightweight and cheap elements out of metalized plastics. Prototypes have been built using a stereolithography process to verify the expected performance by measurements.