Abstract
Novel compact parallel-coupled microstrip bandpass filters are proposed by using additional lumped inductors to realize K-inverters between coupled-line sections to achieve an equivalent to the quarter-wavelength (λ/4) resonator filters. As a result, the filter order can be doubled without increasing the circuit area, and no repeated passband is observed at twice the center frequency. In addition, by introducing the cross-coupling effect, two transmission zeros at upper and lower stopbands may be created. Simple equivalent-circuit models are also established as effective design tools. Specifically, several compact fourth-order microstrip bandpass filters with good stopband rejection are implemented and carefully examined.
Original language | English |
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Pages (from-to) | 2324-2327 |
Number of pages | 4 |
Journal | IEEE Transactions on Microwave Theory and Techniques |
Volume | 53 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2005 |
Keywords
- Bandpass filter
- Coupled line
- Lumped element
- Microstrip