An Accurate Method of Adjusting the Resonant Frequency of Defected Microstrip Structure

An adjustable defected microstrip structure is discussed in detail in this paper. To obtain a better bandstop property, a simple U-shaped slot is etched in the center of microstrip line, the lower insertion loss in the passband and higher rejection level has been exhibited. The resonant frequency is extracted using transmission line network analysis. At the same time, an accurate method of adjusting the resonant frequency is proposed to match the designed resonant frequency exactly. A fabricated sample has been tested to verify the design. Measurement results are in very good agreement with simulations.