Tunable Quarter Mode Substrate Integrated Waveguide filter for 5G communication

In this paper, a miniaturized quarter-mode substrate integrated waveguide (QMSIW) bandpass filter is designed and tuned using PIN diode. The Isosceles triangle based QMSIW is loaded with the circular CSRR to decrease the resonant frequency of the cavity. The QMSIW is designed over the RT/Duroid 5880 substrate whose thickness is 0.254mm. Two pole QMSIW is designed to get a simulated and further a slot is introduced on the top layer to control the position of transmission zero. The simulated value of the insertion and return loss are observed to be -0.61dB and 27.18dB respectively. A novel approach is developed for achieving tunability. PIN diode is placed in the slot and it’s ON and OFF variation are observed. With the ON state of the PIN diode the bandwidth of the filter increases by 580MHz.