Design and Performance Analysis of a High‐Isolation Dual‐Frequency Dual‐Circularly Polarized Antenna

ABSTRACT

This study presents an antenna for global short‐message communication systems, operating in the B2b (1197–1217 MHz) and Lf4 (1610–1630 MHz) bands. To achieve excellent impedance matching within the target frequency ranges, the antenna employs a rhombic cross‐dipole with a central open circular slot, integrated with a top‐loaded circular patch technique. Dual‐circular polarization (Dual‐CP) is realized via a dual‐stub network combined with orthogonal baluns, while the feed network incorporates built‐in high‐pass and low‐pass filters to ensure high port isolation. Additionally, eight equidistantly arranged passive monopole fences are placed around the radiating element to enhance antenna gain at low elevation angles. Experimental results indicate the antenna exhibits a compact form factor (110 mm diameter × 48 mm height) and lightweight design (300 g), with Dual‐CP port isolation exceeding 54 dB. These superior performance metrics make the proposed antenna well‐suited for lightweight satellite systems, demonstrating significant application potential in global satellite short‐message communication scenarios.