Concurrent Dual-Band Microstrip Line Hilbert Transformer for Spectrum Aggregation Real-Time Analog Signal Processing

In this paper, a microstrip line Hilbert transformer is proposed to operate concurrently at dual frequency for spectrum aggregation real time analog signal processing applications. The proposed dual band Hilbert transformer consists of dual band 180° coupler and dual band delay line. The theoretical analysis is carried out to find the relation of coupler and delay line forming closed loop resonance. To verify the proposed design concept, a prototype of Hilbert transformer working at 0.9 GHz and 1.98 GHz is designed and tested, and the simulated and measured results correlate well with each other.