Abstract
A novel microstrip low-pass filter is presented to achieve an ultra-wide stopband with 11 harmonic suppression and very sharp skirt characteristics. The filter is composed of a modified U-shaped resonator (which creates two fully adjustable transmission zeroes), a T-shaped resonator (which determines a cut-off frequency), and four radial stubs (which provide a wider stopband). The operating mechanism of the filter is investigated based on a proposed equivalent-circuit model, and the role of each section of the proposed filter in creating null points is theoretically discussed in detail. The presented filter with 3 dB cut-off frequency (fc = 2.35 GHz) has been fabricated and measured. Results show that a relative stopband bandwidth of 164% (referred to as a 22 dB suppression) is obtained while achieving a high figure-of-merit of 15,221.
Original language | English |
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Pages (from-to) | 945-950 |
Number of pages | 6 |
Journal | ETRI Journal |
Volume | 37 |
Issue number | 5 |
DOIs | |
Publication status | Published - 1 Oct 2015 |
Externally published | Yes |
Keywords
- Microstrip low-pass filter
- U-shaped resonator
- Ultra-wide stopband