# Compact IC-Fed Cavity-Backed CP Crossed-Dipole Antenna with Wide Bandwidth and Wide Beamwidth for SatCom Mobile Terminals

## TL;DR

This paper introduces a compact, wide-bandwidth, and wide-beamwidth circularly polarized antenna for satellite communication mobile terminals.

## Contribution

A novel antenna design using a power-divider/phase-shifter IC and a parasitic arc to achieve wide bandwidth and beamwidth in a compact form.

## Key findings

- The antenna achieves a wide frequency range (1.76–3.08 GHz) with stable circular polarization.
- The design provides wide half-power and axial-ratio beamwidths (≈114–144°) with good pattern stability.
- The compact design supports robust satellite communication under platform motion and low-elevation scenarios.

## Abstract

What are the main findings?
A power-divider/phase-shifter IC replaces conventional quarter-wavelength phase-delay lines to suppress dispersion-induced phase errors and maintain stable and smooth circularly polarized performance over a broad frequency range (1.76–3.08 GHz).A tightly coupled parasitic arc and a downsized cavity jointly broaden the beam, achieving a wide half-power beamwidth (≈114–142°) and 3 dB axial-ratio beamwidth (≈114–144°) with good pattern stability.

A power-divider/phase-shifter IC replaces conventional quarter-wavelength phase-delay lines to suppress dispersion-induced phase errors and maintain stable and smooth circularly polarized performance over a broad frequency range (1.76–3.08 GHz).

A tightly coupled parasitic arc and a downsized cavity jointly broaden the beam, achieving a wide half-power beamwidth (≈114–142°) and 3 dB axial-ratio beamwidth (≈114–144°) with good pattern stability.

What are the implications of the main findings?
The proposed architecture provides a practical route to simultaneously realizing wide bandwidth and wide-beam CP performance in a compact form factor for mobile SatCom terminals.Additional limitations include using a commercial power-divider/phase-shifter IC mitigates dispersion-induced CP degradation, supporting robust links under platform motion and low-elevation satellite scenarios, and facilitating future frequency retuning toward GNSS-related bands.

The proposed architecture provides a practical route to simultaneously realizing wide bandwidth and wide-beam CP performance in a compact form factor for mobile SatCom terminals.

Additional limitations include using a commercial power-divider/phase-shifter IC mitigates dispersion-induced CP degradation, supporting robust links under platform motion and low-elevation satellite scenarios, and facilitating future frequency retuning toward GNSS-related bands.

This paper presents a compact wide bandwidth, wide beamwidth circularly polarized (CP) antenna for satellite communication (SatCom) mobile terminals. The radiator is based on a cavity-backed crossed dipole, while a commercial quadrature power-divider/phase-shifter IC replaces conventional quarter-wavelength phase-delay lines to suppress dispersion-induced phase errors and maintain stable CP performance over a broad frequency range. To broaden the beam, a tightly coupled arc-shaped parasitic strip encircles the tapered semicircular arms, and the cavity cross-section is reduced to enhance lateral radiation. In addition, the cavity sidewalls are electrically connected to the parasitic element to increase the effective electrical length, downshift the operating frequency, and enable miniaturization. A prototype was fabricated and measured. The measured impedance bandwidth (IMBW, |S11| < −10 dB) is 1.76–3.08 GHz, fully covered by the AR < 3 dB bandwidth. The peak gain remains above 2 dBic over 1.7–3.1 GHz, while the half-power beamwidth (HPBW) stays around 114–142° and the 3 dB axial-ratio beamwidth (ARBW, AR < 3 dB) is around 114–144° across the entire operating band. These results indicate that the proposed antenna is a promising candidate for integrated multi-band SatCom terminals requiring wide bandwidth operation and wide-angle coverage.