Microwave Hilbert Transformer and its Applications in Real-time Analog Processing (RAP)

TL;DR

This paper introduces a microwave Hilbert transformer based on a branch-line coupler and loop resonator, demonstrating its design, physical operation, and applications in real-time analog processing tasks.

Contribution

It presents a novel microwave Hilbert transformer design, including transfer function derivation, physical explanation, and experimental validation in RAP applications.

Findings

Successfully demonstrated in edge detection

Effective in peak suppression

Enables single sideband modulation

Abstract

A microwave Hilbert transformer is introduced as a new component for Real-time Analog Processing (RAP). In contrast to its optical counterpart, that resort to optical fiber gratings, this Hilbert transformer is based on the combination of a branch-line coupler and a loop resonator. The transfer function of the transformer is derived using signal flow graphs, and two figures of merits are introduced to effectively characterize the device: the rotated phase and the transition bandwidth. Moreover, a detailed physical explanation of its physical operation is given, using both a steady-state regime perspective and a transient regime perspective. The microwave RAP Hilbert transformer is demonstrated experimentally, and demonstrated in three applications: edge detection, peak suppression and single sideband modulation.