Radio frequency electrically adjusted band-pass filter with constant absolute bandwidth

Abstract

The invention discloses a radio frequency electrically adjusted band-pass filter with a constant absolute bandwidth. The band-pass filter consists of an upper-layer micro-band structure, a middle medium basal plate and lower-layer grounding meta, wherein the upper-layer micro-band structure comprises a first half wavelength resonator, a second half wavelength resonator, an input feed network, an output feed network, an input port and an output port, wherein a fifth micro-band line of the first half wavelength resonator and a seventh micro-band line of the second half wavelength resonator are arranged in parallel to form an interstage coupling structure; the first half wavelength resonator consists of a first micro-band line, a second micro-band line, a third micro-band line, a fourth micro-band line, a fifth micro-band line, a sixth micro-band line and a variable capacitance diode; and the second half wavelength resonator and the first half wavelength resonator have the same structure, and are symmetrically arranged based on the central axis of the interstage coupling structure. The radio frequency electrically adjusted band-pass filter has the characteristics of keeping the absolute constant bandwidth while resonating the center frequency and inhibiting second harmonic wave, and can be applied to the reconfigurable radio frequency front-end in wireless communication.

Description

technical field [0001] The invention relates to a radio frequency electronically adjustable bandpass filter with adjustable center frequency, in particular to a novel half-wavelength resonator and interstage coupling structure applicable to multi-band, wide-band and reconfigurable radio frequency front-end systems , when the center frequency is tuned, the absolute bandwidth remains constant and the electronically adjustable bandpass filter can well suppress the second harmonic. Background technique [0002] Modern ultra-wideband radar and wireless communications require high-performance reconfigurable RF front-ends. For example, in the cognitive radio system, in order to fully utilize and integrate various wireless channels and standards, the RF front-end needs to work at different frequencies, which requires a reconfigurable RF front-end with tunable center frequency. As an important part of the reconfigurable RF front-end, RF electronically tuned band-pass filters are rec...

AI Technical Summary

Problems solved by technology

The existence of these parasitic passbands leads to poor frequency selectivity of the filter, which affects the overall performance of the RF front end

[0006] (3) The insertion loss of the electronically tuned bandpass filter is large and the insertion loss at different frequencies is quite different, which brings inconvenience to the link gain distribution in the system design

In order to reduce the insertion loss, tuning components with high quality factor in the traditional way are necessary, such as MEMS components, which will lead to high design costs

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