A Compact Rectangular Slotted Microstrip Bandpass Filter

This paper presents a compact rectangular slotted microstrip bandpass filter in a 3D planar electromagnetic simulation software called Sonnet Suites. The microstrip filter design is symmetric along the inverse diagonal and consists of a dual-mode microstrip square ring resonator with an alternative perturbation element. This design has a compact rectangular structure of 1 × 1 cm. The substrate used is FR-4 with a dielectric constant of εr = 4.4 and a thickness of 1.6 mm. The filter has a center frequency of 4.33 GHz and a bandwidth of 1.9 GHz, with S12 is nearly zero while S11 is −23 dB. This filter can be implemented between 3 and 5 GHz operating frequencies in wireless.