Bandpass filter play a very vital role in the field of communication. With the advent of large number of communication the devices working a range of frequencies the use of Microstrip technology offers us a very compact realization of a microwave filter thereby reducing the filter size and output parameters. This work presents a tunable dual-band tunable bandpass filter (BPF) with dual band bandpass response with a novel tunable dual-mode character in the range of 1-15GHz and a single band bandpass filter in the range of 1-10GHz. The proposed dual band bandpass filter design primarily consists of tunable components such as varactor diodes and capacitances to bring about tunability in the filter design. The circuit designed is a Triple U-shaped circuit so as to obtain a compact filter structure which has varactor is placed at the center of the microstrip circuit and capacitances so as to produce a tunable bandpass filter response. This approach has enhanced the tunability of the proposed dual band filter by tuning the varactors and capacitances present in the circuit, thereby exhibiting a uniform tuning range with a minor changes in the values of the capacitor and varactor. Therefore, a uniform tuning is obtained by employing capacitance and varactor and the circuit can maintain nearly a constant bandwidth over the tuning range. The single band filter is designed to work in the range of 1-10GHz where the single band can be tuned between the entire operating frequencies. Simulated results are found to be more efficient. The S-Parameter [S (2, 1)] results for the dual band bandpass filter show that the first passband can be tuned in a frequency range from 2.4 to 4.45 GHz, whereas the second passband varies from 8.5 to 11 GHz.
Volume 11 | 04-Special Issue
Pages: 2391-2402