Design of 800 W High-Power Low-Pass Filter with Finite Metal Thickness Based on Elliptic Function Response

This paper presents a design method of 800 W high power filter with finite metal thickness based on elliptic function response. By increasing the metal thickness of the microstrip line, the power-handling capability of the filter can be improved. The impedance and waveguide wavelength of microstrip lines with finite metal thickness will undergo significant changes. This paper introduced a design methodology for transitioning from prototype circuits to microstrip filter designs with finite metal thickness, demonstrating its application through the design of two low-pass filters. Testing performed at an input power of 800 W reveals that filter 1 exhibits a cut-off frequency of 4 GHz. It maintains a return loss better than −15 dB between 2.15 GHz and 3.55 GHz, with an insertion loss of less than 0.3 dB. Additionally, it achieves harmonic suppression of −20 dB at 12.2 GHz. Filter 2, featuring an increased number of resonators, offers a wider band and sharper edge steepness. Within the range of 1.8 GHz to 4.4 GHz, it maintains a return loss better than −15 dB and an insertion loss of less than 0.3 dB. Moreover, it achieves harmonic suppression of −20 dB at 13 GHz.