Real-Time Flexible Temporal Sequence RF Spectrum Sniffer With RF Processing Group Delay Network

In this letter, a real-time spectrum sniffer is presented to achieve flexible temporal sequence from radio frequency (RF) signal processing group delay network (GDN). The proposed sniffer is composed of a Wilkinson power divider and two branches of RF processing GDN, where multiple group delay units (GDUs) are cascade. The GDU is an RF processing function designed from a coupler and a feedback delay line, where the variable group delay is realized by controlling the electrical length of feedback delay line. Compared to other works, the proposed design features a flexible spectrum temporal sequence, high scalability for multichannel spectrum sniffing, simplified design topology, and large group delay with relatively low transmission loss. To validate the design concept, a prototype is designed and measured, and both time-domain and frequency-domain verification are carried to demonstrate spectrum sniffing characteristic.