A novel of square loop resonator band pass filter by using cross-shape input/output coupling for 9GHz application

Filter in telecommunication is a device which has function like a frequency band selector. it plays an significant role especially to select the frequency band that is wanted to be passed through. At this advanced technology era where every device is getting compact in design and size, the filter model also has been challenged in order to meet and fit the recent situation. The microstrip filter is the answer to that challenge. This type has been chosen in this research because its simplicity in the design and easy to be implemented. One of the method in designing a microstrip filter is Square Loop Resonator which also known as SLR filter. To increase the filter performance, a few components like perturbation area and bends has been applied in this design. An unique modification of this proposed filter design is the coupling at input/output port which have cross shape. The investigation result has shown that this shape helps in making the bandwidth narrower than the usual coupling design and also it can shift the frequency center value. In this research the filter is planned to be printed on Rodgers Duroid PCB material with relative permittivity (ϵ
r
) 11.5. Higher value of ϵ
r
is used to make the filter dimension smaller. The result of the SLR filter with modified coupling input/output design has shown that this device has center frequency at 9GHz and 330MHz bandwidth. The total size of this filter is 15.2cm × 16.2 cm.