Evaluating the influence of the magnetic permeability of the microstrip modal filter substrate on its frequency characteristics

Abstract

This paper considers the possibility of improving the characteristics of modal filters by using composite materials with a relative magnetic permeability of μ r >1. The influence of the magnetic permeability of the microstrip modal filter substrate on its frequency characteristics is investigated. The paper presents the frequency dependences |S 21| of the filter with lengths l=1, 0.5, and 0.2 m and with μ r = 1, 4, 7, and 10. It is shown that the increase of the the μ r value leads to a decrease in the filter bandwidth.