Microstrip BPF made of square loop resonator for X-band weather radar

Filter in telecommunication is a device which has function as a frequency band selector. They are supposed to pass the desired frequencies and block or suppress the unwanted ones. Filter has been used widely especially in radar system. There are various methods to design a bandpass filter especially for higher frequency. Microstrip filter type is 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. The filter that will be designed have center frequency at 9GHz with 50MHz bandwidth. The filter is planned to be printed on Rodgers Duroid PCB material with relative permittivity (ϵ
_r
) 10.6. Higher value of (ϵ
_r
) is used to make the filter dimension smaller. The result of this design is a SLR bandpass filter with resonator size 13cm X 13cm with the final PCB size of this filter is 30cm X 18 cm. The simulation result of this design has shown that the filter has center frequency at 9GHz and 55.2MHz bandwidth, 5.2MHz wider than had planned.