Two-Tone Excited Hybrid-Coupler-Based Intermodulation Generator for High-Isolation Wireless Sensing Applications

Abstract

An intermodulation generator is designed and presented with integration of a hybrid coupler and two identical Schottky diodes (i.e., D1 and D2). The connection polarities of D1 and D2 to the direct and coupled ports of hybrid coupler are opposite for its rapid realization of balanced intermodulation generation. Due to the superior coupling characteristics of hybrid coupler, it can distribute an incident two-tone signal to the direct and coupled ports evenly for D1 and D2, and deliver the balanced intermodulation generations to the isolation port highly insulated from its incident port. Two identical quarter-wavelength shorted stubs at the fundamental frequency are implemented by suppressing the second-order spectrums for an enhancement of the balanced intermodulation generations. Both theoretical analysis and experiments validate the presented intermodulation generator design, which can highly isolate its incidences (the two tones) and outputs (the intermodulation generations) for the future high-isolation wireless sensing applications. INDEX TERMS Hybrid coupler, two tones, intermodulation, Schottky diodes, wireless sensing.

Two-Tone Suppressed Third-Order Intermodulation Transponder Based on Transmission-Line-Based Fourth-Order Filter Combined Matching Network

“…Furthermore, the use of two frequencies can increase the complexity of a radar transceiver. However, intermodulation transponders, which receive multi-tone fundamental signals and transmit intermodulation signals, have the potential for simpler circuitry and fewer components [14], [15]. This potential is advantageous in terms of the design complexity, circuit size, and spectrum efficiency, primarily because of the similarity between transmission and reception frequencies.…”