Design of a narrow-band filter operating at 1420 mhz forradio astronomy applications

1420MHz is one of the frequency values used in radio astronomical measurements. The properties of atomic hydrogen clouds are detected through radio observations at 1420MHz, and measurements are conducted using the RF block of radio telescope systems. Bandpass filters are critical components of this RF block.In this thesis, a narrowband microstrip bandpass filter operating at the 1420MHz frequency, designed specifically for radio astronomy applications, was developed using the half-wavelength open-circuit stub filter method. Harmonic suppression studies were conducted by adding quarter-wavelength short-circuit stubs to the designed filter. To enhance the electromagnetic compatibility of the filter and prevent interference issues, a GCPW (Grounded Coplanar Waveguide) structure was implemented, and grounding vias were added around it.Three-dimensional electromagnetic simulations were performed using the AWR simulator during the design process, and stub lengths were optimized to achieve the desired design criteria. It has been observed that the theoretical and practical results of the filter produced using ROGERS 4350B dielectric material are in good agreement. The resulting filter exhibited a bandwidth of approximately 100MHz and a reflection loss (S11) of -30 dB. These findings indicate that the filter offers high selectivity, significant return loss, and effective suppression of undesired frequencies, making it ideal for both academic and applied research purposes.