Compact, Reflectionless Band-Pass Filter: Based on GaAs IPD Process for Highly Reliable Communication

For highly reliable and compact communication of front-end modules, a miniaturized reflectionless band-pass filter, based on the GaAs integrated passive device (IPD) process, is proposed in this work. The stop-band signal absorption rate of the filter can reach more than 90% and greatly reduce the influence of electromagnetic interference for sensitive devices. First, a circuit topology of reflectionless filter is proposed. Then, the miniaturized reflectionless band-pass filter is designed and fabricated based on GaAs IPD process with a compact size of only 0.85 mm × 1.33 mm × 0.09 mm (0.011λ × 0.018λ × 0.001λ). The filter operates at frequency ranging from 3.3 GHz to 4.5 GHz for 5G communication, the insertion loss (S21) is less than 3 dB, the return loss in the passband (S11) is over 15 dB, the stopband return loss (S11) is over 10 dB, and the out-of-band suppression (S21) reached 19 dB. All the measured results are in good agreement with the simulated results. It shows great potential in the process of designing highly reliable and compact monolithic integrated wireless modules and wearable electronics.