© The Institution of Engineering and Technology
A novel microstrip lowpass filter with outstanding features is designed, simulated, fabricated and analysed. The proposed structure has the capability to improve frequency response in transition band and remove the 13th unwanted harmonics in the stopband. The proposed design comprises many resonators and cell attenuators. It features an UW stopband, high suppression factor and high sharp roll-off. To adjust the cut-off frequency, the transfer function and LC equivalent circuit of the main resonator are calculated. Results show that cut-off frequency and relative bandwidth of stopband of the filter are 2 GHz and 171%, respectively. Also, insertion loss <0.11 dB and return loss more than 18 dB have obtained for filter form DC to 2 GHz. The fabricated filter reaches a high figure of merit of 72,093.
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