A Complex Impedance Matched Circularly Polarized Filter Antenna

Abstract

A complex impedance matching circular polarization filter antenna includes two dielectric substrates and three metal layers, and the space between the two substrates is filled with air. The antenna radiating unit is located on the top layer of the first dielectric substrate and is a circular metal patch with notches. The ground metal layer is located on the upper layer of the second-layer substrate and is etched with an asymmetrical U-shaped groove. The filter feeding structure is located on the bottom layer of the second-layer substrate, and a hairpin microstrip resonator is connected to the terminal of the microstrip line. In the present invention, by adjusting the size of the U-shaped microstrip line resonator and the coupling slit, the quality factor and the coupling coefficient in the coupling matrix are tuned, and the complex impedance matching of the antenna can be realized; through the U-shaped microstrip line resonator and the circular SMD resonance tuning expands the working bandwidth of the antenna and realizes second harmonic suppression at the same time. The invention can ensure the second harmonic suppression and complex impedance matching while realizing the broadband operation of the antenna.

Description

technical field [0001] The invention belongs to the technical field of antennas and microwaves, and relates to a filter antenna. Background technique [0002] In the existing wireless radio frequency system, various circuits such as the antenna and filter of the radio frequency front-end are mostly independently designed, and then connected together through radio frequency connectors and cable levels, there are problems such as impedance matching and additional insertion loss. In the filter antenna design, the antenna becomes a component of the filter circuit, and it is necessary to design, simulate and optimize the antenna and filter circuit at the same time. [0003] Compared with traditional antennas, filter antennas do not require a separate impedance matching network between the antenna and the RF circuit, and also have advantages such as compact size, low loss, wide bandwidth, high-frequency selectivity, broadband harmonic suppression, improved out-of-band rejection an...

AI Technical Summary

Problems solved by technology

[0004] The technical problem solved by the present invention is: aiming at the deficiencies of the prior art, a complex impedance matching circular polarization filter antenna is proposed, which utilizes the characteristics of each resonator in the filter antenna to realize broadband operation and harmonic suppression, and then adjusts each resonance The quality factor and coupling coefficient of the filter are used to achieve complex impedance matching, which solves the problems of increased loss and complex structure caused by the introduction of filters and impedance matching networks in traditional conventional designs.

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