# Circularly Polarized X-Band Fan-Beam Antenna and Its Application to Offset Reflector Systems

## TL;DR

This paper introduces a circularly polarized antenna array that produces a fan-beam pattern and improves performance when used in offset reflector systems.

## Contribution

The novelty lies in the design of a CP 4 × 4 array with a wide axial ratio bandwidth and its successful application in offset reflector systems.

## Key findings

- The antenna achieves a wide axial ratio bandwidth of 1.9 GHz centered at 8.2 GHz.
- The offset reflector system using this antenna achieves a gain enhancement of approximately 17 dB.
- The fabricated antenna matches simulation results in terms of impedance, gain, and radiation characteristics.

## Abstract

In this letter, a circularly polarized (CP) 4 × 4 array antenna generating a fan-beam radiation pattern is presented, along with its application as the primary pattern of an offset reflector antenna. A sequentially rotated feed network is incorporated into the proposed antenna, enabling a wide axial ratio (AR) bandwidth of 1.9 GHz centered at 8.2 GHz. The proposed array antenna generates about 27.5° and 14.5° of half-power beamwidth (HPBW) in ϕ=0° and ϕ=90° planes, respectively. The fabricated antenna shows good agreement with the simulated results in terms of impedance bandwidth, gain, and radiation characteristics. Furthermore, the offset reflector antenna fed by the proposed CP array is evaluated, resulting in a gain enhancement of approximately 17 dB and a fan-beam radiation characteristic with half-power beamwidths of 3.95° and 2.15°, with an axial ratio bandwidth of 1 GHz.