A High-Performance Dual-Band Switchable Bandpass Filter and Its Application in 5G Signal Detector

With the development of communication technology, the allocation of frequency spectrum is becoming more intensive. As an important communication component, reconfigurable filters are widely used in various parts of the communication system. We demonstrate a dual-band reconfigurable (switchable) microstrip bandpass filter working in two sub-6-GHz frequency bands based on controllable grounding topology (CGT), which can achieve an ultrafast tuning speed up to ~2 ns, a low bias voltage of ~3.0 V, and a high linearity up to +42.5 dBm in third-order intercept point (IP3). We also use the multilayer design to reduce the interference of the bias circuit, and finally, a portable 5G signal detector is proposed, showing the promising application prospects of the proposed switchable bandpass filter.