A Butler Matrix with Miniaturized Patch Structure

Abstract

The invention discloses a Butler matrix with a miniaturized patch structure, which includes a symmetrical Butler matrix formed by connecting multiple square patch couplers and multiple square patch phase shifters, each square patch The surface etching of the square patch coupler has the first cross groove that changes the circuit density distribution on the surface of the square patch coupler and generates additional parallel inductance to reduce radiation loss. The surface etching of each square patch type phase shifter is changed. The circuit density distribution on the surface of the square patch type phase shifter and the second cross slot that generates additional parallel inductance to reduce radiation loss; the overall size of the Butler matrix can be reduced by etching the cross slot on the coupler and phase shifter , can also change the current density distribution on its surface, so that the current density distribution in the upward and downward directions is generated, which helps to reduce the radiation loss generated by the patch resonator.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a Butler matrix with a miniaturized patch structure. Background technique [0002] The beamforming network is a key part of multiple-input multiple-output (MIMO) wireless communication, and the Butler matrix is ​​a switchable beamformer proposed by Butler in 1961. It contains N input ports and the same number of output ports or radiating units. When a signal is introduced at a certain input port, equal-amplitude excitation is generated at all output ports, and there is a constant phase difference between them. Radiation can be generated in a certain angular direction in space, that is to say, it can make the antenna array evenly distributed. [0003] However, the size of the traditional Butler matrix is ​​mainly determined by the wavelength of the radio frequency band, so its size is usually fixed for the wavelength used in the design, and generally speaking, the ...

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Problems solved by technology

[0003] However, the size of the traditional Butler matrix is ​​mainly determined by the wavelength of the radio frequency band, so its size is usually fixed for the wavelength used in the design, and generally speaking, the size is relatively large. This fixed large size is no longer sufficient. The miniaturization requirements of today's rapidly developing wireless technology; secondly, with the continuous expansion of application platforms, the number of Butler matrices used continues to increase, and the number of intersection points increases significantly, resulting in increased loss and complexity of the overall structure; And because the open patch has the advantage of improving radiation efficiency, it is widely used in antenna design, but it will cause potential high radiation loss in the design of planar circuit, although this radiation loss can be solved by rotating the electric thin film substrate However, it will lead to some other adverse effects, such as the increase of conductor loss; of course, a cavity can also be used to shield the patch module to avoid radiation loss, but there will be parasitic resonance between the corresponding cavity and the patch module , but also increases cost, weight and volume

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