The invention discloses a
broadband filter with adjustable trapped wave. The
broadband filter comprises a single-layer quarter-mode substrate integrated
waveguide resonant cavity, wherein a
signal metal layer is in the shape of an isosceles
right triangle, a
signal input
microstrip line and a
signal output
microstrip line are arranged along the two right-angle sides of the signal
metal layer respectively, a first gap is etched in the position, close to the signal input
microstrip line, of the signal
metal layer, a second gap is etched in the position, close to the signal output microstrip line, of the signal metal layer, a first adjustable device is arranged in the first gap, and a second adjustable device is arranged in the second gap. According to the invention, a variable
capacitance diode is loaded in the port gap of the
broadband filter, a bias
voltage is loaded at two ends of the variable
capacitance diode, a narrow stop band can be superposed on the basis of the original broadband of the broadband filter so as to introduce the trapped
wave frequency, the continuous adjustment of the trapped
wave frequency in a full-
passband range can be realized by changing the
capacitance value of the variable capacitance
diode, and a
PIN diode is utilized to play a role in adjusting the frequency, so that the self-adaptive capability of the broadband filter is enhanced.