Design of compact microstrip lowpass filter with ultra-wide stopband using modified T-shaped resonator. Issue 6 (9th September 2014)

• Record Type: Journal Article
• Authors: Afzali, Behnam; Karkhanehchi, Mohammad Mehdi; Karimi, Gholamreza
• Is Part Of: International journal of microwave and wireless technologies. Volume 7:Issue 6(2015)
• Page Start: 699
• Page End: 703
• Publication Date: 2014-09-09
• Subjects: Lowpass filter, -- Transmission zero, -- LC equivalent circuit; Wireless communication systems -- Periodicals; Microwave circuits -- Periodicals; Radio frequency -- Periodicals; 621.381305
• DOI: 10.1017/S175907871400124X
• Languages: English
• ISSNs: 1759-0787

Abstract

Abstract : A new microstrip lowpass filter with compact size and ultra-wide stopband using T-shaped resonator is proposed. To make smaller the circuit size of the filter, cursive transmission line is also suggested. Moreover, exact equation of most important transmission zero is calculated based on LC equivalent circuit and transformation function. A demonstration filter with 3 dB cut-off frequency at 1.02 has been designed, fabricated, and measured. Results show that a relative stopband band width of 166.3% (referred to suppression degree of 20 dB) is achieved while obtaining high figure of merit of 46 274.