Design and Simulation of Microstrip Bandpass Filter Techniques at X-Band for RADAR Applications

A new approach to compact bandpass filter techniques such as end-coupled, parallel-coupled, hairpin, interdigital, and combline filters with their enhancement in size and frequency performance is introduced in this paper. Designed fifth-order filters that are simulated in the compact narrowband frequency is targeted for high selectivity, better return loss, and insertion loss with a passband ripple using Chebyshev response. To minimize the dimension of filters, we implemented an optimized design by determining its parameters, coupling resonators, and connecting elements. The results are simulated using Genesys Keysight software and iterated for the desired specimen. The prototype filter consists of Rogers RT/duroid 5880 substrate with a thickness of 0.508 mm. Experimental result of hairpin filter structure shows a reduced design (20.2 mm × 10 mm) and improvises the stopband characteristics with better harmonic suppression and narrower frequency bandwidth than the other conventional filter for future development in RADAR applications.