Design of Artificial Transmission Line and Low-Pass Filter Based on Aperiodic Stubs on a Microstrip Line

Among many microstrip configurations, the open-circuited shunt stub is probably the most common and versatile one. It is capable of performing a wide range of functions. Despite extensive studies and applications of the open-circuited shunt stub, comparatively little is known about aperiodic stubs on a microstrip line. In this paper, aperiodic stubs on a microstrip line are exploited to implement a high-performance low-pass filter and a joint design of the artificial transmission line and low-pass filter. The experimental results validate the performance of the proposed circuits. For the low-pass filter application, the proposed circuit outperforms a seventh-order Butterworth filter while their circuit sizes are comparable. For the joint design, it may potentially enhance the degree of integration in RF and microwave systems.