Novel band limiting-adjustable ultra-wideband bandpass filter

Abstract

The invention discloses a novel band limiting-adjustable ultra-wideband bandpass filter. The filter uses the inherent zero point of a multimode resonator to form band limiting in the ultra-wideband bandpass filter, a step impedance resonant structure and a branch-loaded resonant structure are combined, a novel T-type multimode resonator is formed, a capacitor is parallelly connected onto impedanceconversion of the step impedance resonant structure, the number of resonant modes is increased, a varactor is loaded to the terminal of the resonator, and the varactor is used to adjust the zero point position in the band to form adjustable band limiting characteristics. The novel band limiting-adjustable ultra-wideband bandpass filter mainly comprises an upper-layer microstrip structure, a middle-layer dielectric plate and lower-layer grounding metal, has the characteristics of simple structure, miniaturization, good features and the like, can overcome the shortcoming of insufficient filterselectivity based on the multimode resonator design, realizes good selectivity and harmonic suppression effects, and is easy to realize circuit integration and system packaging.

Description

technical field [0001] The invention relates to the field of adjustable circuit theory, in particular to a novel band-limited adjustable ultra-wideband band-pass filter. Background technique [0002] Since the U.S. Federal Communications Commission (FCC) issued the application license of ultra-wideband (Ultra-wideband, UWB) technology in the field of short-distance wireless communication on February 1, 2002, it has promoted the marketization process of broadband / ultra-wideband technology products, This makes the research of broadband / ultra-wideband system and its devices get more attention. Ultra-wideband (3.1GHz-10.6GHz) covers a very wide range and overlaps with the range of other wireless services (such as 4.2-4.4GHz for aviation radio navigation (ARNS), 5.8GHz for wireless area local area network (WLAN), and 8.5 -10.68GHz radar frequency band (ITU) of the International Telecommunication Union. These wireless service frequency bands may interfere with ultra-wideband sign...

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Problems solved by technology

In recent years, many scholars have been working on the study of ultra-wideband bandpass filters with adjustable band-limiting, such as literature 1 (SongK, Xue Q. Inductance-Loaded Y-Shaped Resonators and Their Applications to Filters[J]. IEEE Transactions on Microwave Theory&Techniques, 2010, 58(4):978-984) and literature 2 (Xu J, Wu W, Kang W, et al.Compact UWB Bandpass Filter With a Notched Band Using Radial Stub Loaded Resonator[J].IEEE Microwave and Wireless Components Letters ,2012,22(7):351-353) introduced several structures of band-limited tunable filters in detail. The disadvantages of the previously designed band-limited tunable filter structures are as follows: (1) Bandwidth adjustment The range is limited; (2) During the adjustment process, the filter performance is unstable; (3) The varactor diode introduces parasitic parameters, causing unnecessary resonance, and the power supply increases the circuit size

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