# A Low-Profile Dual-Polarized High-Gain Low Cross-Polarization Phased Array for Ku-Band Satellite Communications

## TL;DR

This paper presents a new low-profile phased array antenna for Ku-band satellite communications with high gain and low cross-polarization.

## Contribution

The paper introduces a novel dual-polarized shared-aperture phased array with minimized cross-polarization and high gain.

## Key findings

- The proposed phased array achieves an impedance bandwidth of around 21.1% with in-band isolations above 36.7 dB.
- Prototypes achieved gains of up to 29 dBi and 32.4 dBi, demonstrating high performance for satellite communications.
- The design supports beam-scanning for dynamic satellite communications using T/R phase-shifting modules.

## Abstract

A low-profile dual-polarized shared-aperture phased array antenna is proposed for Ku-band satellite communications in this paper. The stacked octagonal patches loaded with Via-rings are proposed as dual-polarized shared-aperture radiation elements, with the characteristics of wide impedance bandwidth, high gain, and weak coupling. Furthermore, innovative minimized three-port ring couplers are utilized for the differential-fed antenna array, further suppressing the cross-polarization component. Substrate integrated coaxial line (SICL) and microstrip line (MS) feed networks are employed for the excitation of transmitting band (Tx) horizontal polarization and receiving band (Rx) vertical polarization, respectively. The non-uniform subarray architecture is optimized to minimize the sidelobe levels with the reduced number of transmitter and receiver (T/R) radio frequency phase-shifting modules. As proof-of-concept examples, 16 × 24 and 32 × 24 array antennas are demonstrated and fabricated. The measured impedance bandwidths of the proposed phased array antennas are around 21.1%, while the in-band isolations are above 36.7 dB. Gains up to 29 dBi and 32.4 dBi are performed by two prototypes separately. In addition, the T/R phase-shifting modules are utilized to validate the beam-scanning characteristic, which is of value for dynamic satellite communications.