Band-gap adjustable micro-strip ultra-wide band filter

Abstract

The invention discloses a band-gap adjustable micro-strip ultra-wide filter, which is mainly used for solving the problems that the band-gap loading ultra-wide filter has out-of-band suppression difference, bigger band gap width and independent turning of double band gaps. The filter comprises a micro-strip medium substrate (1), a metal grounding plate (2), a multi-mode resonator (3), a pair of input-output interdigital micro-strip feeder lines (4), a defected ground structure (5) and a direct-current biasing circuit (11), wherein a T-shaped branch (6) is loaded in the center of the multi-mode resonator (3); a band gap resonator (7) is loaded on the lower surface of the multi-mode resonator (3); the band gap resonator consists of two symmetrical stepped-impedance resonators (71, 72) and a variode (10); and capacitance value of the variode (10) is controlled by adjusting the biasing voltage of the direct-current biasing circuit (11). The band-gap adjustable micro-strip ultra-wide band filter is small in dimension, narrow in band gap width, good in out-of-band suppression difference, is capable of realizing continuous adjustment of the first band gap, is capable of keeping the second band gap constant and can be used for a wireless communication system.

Description

technical field [0001] The invention belongs to the technical field of electronic devices, and in particular relates to an adjustable microstrip ultra-wideband filter, which can be used for a radio frequency front end of a wireless communication system. Background technique [0002] With the rapid development of wireless communication technology, people's requirements for information technology are getting higher and higher. Ultra-wideband UWB technology has the advantages of simple system, low power consumption, good concealment, strong multipath resolution ability, fast data transmission rate and low cost. , high security and other advantages, making it a research hotspot in the field of wireless communication. The communication frequency range of the UWB system is 3.1GHz to 10.6GHz. Due to its wide frequency band, the frequency band overlaps with some narrowband systems, such as the WiMAX system with a frequency of 3.5GHz and the WLAN system with a frequency range of 5.2G...

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Problems solved by technology

In March 2008, H.R.Arachchige and others published "UWB Bandpass Filter with Tunable Notch on Liquid Crystal Polymer Substrate" on Microwave Conference.2008 (APMC2008).Asia-Pacific (Dec.16-20,pp.1-4,2008). ", proposed a bandgap tunable ultra-wideband filter, which can realize a continuously adjustable bandgap, but the bandgap width increases with the increase of frequency, which will occupy the effective communication frequency band; 2011 In January 2011, Feng Wei et al published "Compact UWB Bandpass Filter With Dual Notched Bands Based on SCRLH Resonator" in IEEE Transactions on Microwave Theory and Techniques journal (vol.21, no.1, pp.28-30, 2011) , a novel dual-bandgap ultra-wideband filter is proposed, which has two fixed-frequency bandgaps, but both bandgaps are not adjustable, and the bandwidth is wider

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