High-Performance Circularly Polarized Array Antenna utilizing Gap Waveguide Technology for Satcom Application

Licentiate thesis, 2025

This thesis introduces a novel circularly polarized array antenna utilizing Ridge Gap Waveguide
(RGW) technology, designed for Ka-band satellite communication. The proposed 8×8 array achieves
a peak gain of 27 dBi at the center frequency of 28.75 GHz, with a relative first sidelobe level below
-13 dB. The antenna demonstrates excellent axial ratio performance, remaining below 3 dB across a
bandwidth of 8.6% (27.5–30 GHz). A total efficiency of 84% is achieved, placing this design among
the most efficient solutions for Ka-band satellite applications.
The antenna employs a U-shaped slot backed by a ridge-loaded cavity, a configuration that min-
imizes mutual coupling while maintaining high radiation efficiency. The compact design consists of
only two layers and is fed by a ridge gap waveguide-based corporate feed network, ensuring even
power distribution and phase alignment. Compared to conventional waveguide-based designs, the
RGW structure offers simplified manufacturing and superior performance, making it well-suited for
high-gain, high-efficiency satellite antennas.
Innovative decoupling and feeding techniques are explored in this work, providing robust signal
integrity and minimizing far-out sidelobes. The findings establish this design as a strong candidate for
next-generation satellite communication systems, with potential for scalable, cost-effective produc-
tion