Saeed Zolfaghary Pour

arXiv2026

A Fully Reconfigurable RF Vector Modulator based Wideband Phase Shifter for NextG Beamforming Phased Array in Satellite Communications (SATCOM)

This paper presents a fully reconfigurable RF vector modulator (RFVM)-based phase shifter for wideband beamforming phased array of 6G/NextG satellite communication (SATCOM). It covers the frequency range from S-band up to Ku-band. Specifically, the proposed RFVM features a novel vector modulation approach that relaxes the frequency constraint in conventional scenario while avoiding applying a quarter all-pass filtering (QAF) network. It achieves a topology that RF input signal is divided into multi-branch transversal sections where each branch enables individual gain weightings and phase delays. By resumming the signals from all branches, the output signal of proposed RFVM can realize a full 360 degree phase shifting while it preserves magnitude response in wideband scenario.

eess.SP↗

arXiv2024

A Low-Cost Monopulse Receiver with Enhanced Estimation Accuracy Via Deep Neural Network

In this paper, a low-cost monopulse receiver with an enhanced direction of arrival (DoA) estimation accuracy via deep neural network (DNN) is proposed. The entire system is composed of a 4-element patch array, a fully planar symmetrical monopulse comparator network, and a down conversion link. Unlike the conventional design topology, the proposed monopulse comparator network is configured by four novel port-transformation rat-race couplers. In specific, the proposed coupler is designed to symmetrically allocate the sum (Σ) / delta (Δ) ports with input ports, where a 360° phase delay crossover is designed to transform the unsymmetrical ports in the conventional rat-race coupler. This new rat-race coupler resolves the issues in conventional monopulse receiver comparator network design using multilayer and expensive fabrication technology. To verify the design theory, a prototype of the proposed planar monopulse comparator network operating at 2 GHz is designed, simulated, and measured. In addition, the monopulse radiation patterns and direction of arrival are also decently evaluated. To further boost the accuracy of angular information, a deep neural network is introduced to map the misaligned target angular positions in the measurement to the actual physical location under detection.

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