Design and Implementation of C-Band Large-Power Planar Butler Matrix in SRS

Abstract

In satellite remote sensing (SRS), there is a demand for large-power microwave components. A Butler matrix is essential to a transmitting antenna array in SRS. This article illustrates the electrical and mechanical design, simulation, and test results of a large-power planar beamforming network for SRS at C-band. It is a 4 × 4 Butler matrix based on square coaxial lines. Short-ended stubs are used in the Butler matrix to broaden its bandwidth by 10%, support inner conductors, and enhance heat transfer in vacuum environments. The simulation results are consistent with the measured results. The reflection coefficient is less than −18 dB, and the isolation is more than 23 dB from 3.8 GHz to 4.2 GHz. The insertion losses are less than 0.6 dB, and the phase errors are better than ±6°. The measured peak microwave power of the proposed Butler matrix is 9 kW. Its size is 440 × 400 × 40 mm3. The proposed Butler matrix beamforming network can be applied to SRS systems.

A Multi-Aperture Technique for Longitudinal Miniaturization of UWB 3 dB Dual-Layer SIW Coupler

“…A microwave coupler is a key component in wireless systems and is characterized by its bandwidth and size, among other parameters. In many emerging systems, such as multi-beam array antenna [ 1 ], Nolen/Butler/Blass matrix [ 2 , 3 , 4 , 5 , 6 ], frequency diverse array radar [ 7 , 8 ] or load modulated balanced amplifier [ 9 ], microwave couplers are required in large numbers, and their miniaturization can lead to a significant size reduction in the overall sensing systems, such as radars, LiDARs and other test equipment such as vector network analyzers and radio communication testers.…”