Abstract
A narrowband dual-band bandpass filter (BPF) with independently tunable passbands is presented through a systematic design approach. A size-efficient coupling system is proposed with the capability of being integrated with additional resonators without increasing the size of the circuit. Two flag-shaped resonators along with two stepped-impedance resonators are integrated with the coupling system to firstly enhance the quality response of the filter, and secondly to add an independent adjustability feature to the filter. The dual passband of the filter is centered at 4.42 GHz and 7.2 GHz, respectively, with narrow passbands of 2.12% and 1.15%. The lower and upper passbands can be swept independently over 600 MHz and 1000 MHz by changing only one parameter of the filter without any destructive effects on the frequency response. According to United States frequency allocations, the first passband is convenient for mobile communications and the second passband can be used for satellite communications. The filter has very good in- and out-of-band performance with very small passband insertion losses of 0.5 dB and 0.86 dB as well as a relatively strong stopband attenuation of 30 dB and 25 dB, respectively, for the case of lower and upper bands. To verify the proposed approach, a prototype of the filter is fabricated and measured showing a good agreement between numerically calculated and measured results.
Highlights
Microstrip technology has been widely used in modern communication systems since it is a mature and highly reliable technology for microwave- and millimeter-wave applications [1,2,3,4,5,6,7,8,9,10,11]
Distributed filters composed of many resonators can be a desired solution to satisfy the satellite communication requirements, such as high selectivity and low dissipation loss, such configurations lead to a circuit size with dimensions of several wavelengths, making the microwave front-end filters one of the bulkiest elements in the RF payload
The frequency response of the prototyped dual-band bandpass filter (BPF) is measured by the Agilent N5230A (Agilent Technologies, Santa Clara, CA, USA) network analyzer
Summary
Microstrip technology has been widely used in modern communication systems since it is a mature and highly reliable technology for microwave- and millimeter-wave applications [1,2,3,4,5,6,7,8,9,10,11]. The C-band covers 4 GHz to 8 GHz in the microwave range used for weather radar systems and mobile and satellite communications (Satcom). In relation to satellite communication systems, the design of microwave filters has challenges associated to several factors, which include the spectrum scarcity and host environment. Distributed filters composed of many resonators can be a desired solution to satisfy the satellite communication requirements, such as high selectivity and low dissipation loss, such configurations lead to a circuit size with dimensions of several wavelengths, making the microwave front-end filters one of the bulkiest elements in the RF payload
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
