Designing of Dual Bandpass Microwave Filter

Abstract

1.1 INTRODUCTION Filter is a two-port network used to control the frequency response at a certain point in an RF or microwave system by providing transmission at frequencies within the pass-band of the filter and attenuation in the stop-band of the filter. Typical frequency responses include low-pass, high-pass, bandpass, and band-reject characteristics. Filters are frequently used in a large number of fields of electrical and electronics engineering. The filter is a frequency selective device; it can be utilized for selecting a particular band of frequency from a wide range of frequency spectrum. In voice frequency telegraphy, multichannel communication is possible by utilizing a number of bandpass filters or simply a multiband filter. Many filters are used in various stages in TV receivers, where they can be used for producing intermediate combined sound and picture carrier frequency and then can separate sound carrier from the composite video signal. In audio amplifiers, filters are used to reduce harmonic distortion and voice rejection. Filters are mainly categorized into two categories: 1. Active Filters 2. Passive Filters Active filters use amplifying elements, especially op amps, with resistors and capacitors in their feedback loops, to synthesize the desired filter characteristics.