Helical antenna with small reflection surface

Abstract

The invention discloses a helical antenna with a small reflection surface, aiming at improving the helical antenna gain, enlarging the launching coverage range of a launcher and meeting the long-distance communication requirement of a tire pressure monitor system (TPMS). The helical antenna comprises a body and the reflection surface, wherein the body has a spiral structure formed by winding a metal wire or a metal tube, and is a normal mode helical antenna; and the reflection surface is arranged under the body and is connected with a negative pole or a ground wire of a feeding point of the body. The reflection surface meets the condition that (D0-D) / 2 is more than or equal to A-x and less than or equal to A, wherein D is the screw diameter of the body, D0 is the diameter of the reflection surface, A and x are constants, x is more than 0 and less than A, A is more than x and less than or equal to 0.01 lambda, and lambda is the wavelength of a signal transmitted by the launcher within the free space.

Description

technical field [0001] The present invention relates to transmitters suitable for use in tire pressure monitoring systems (TPMS systems) for trucks or mass vehicles, and more particularly to helical antennas with small reflective surfaces for such transmitters. Background technique [0002] The tire pressure monitoring system (TPMS) is mainly used to detect the pressure and temperature of automobile tires, to give early warning of possible dangers caused by tire pressure and temperature, to ensure driving safety, and to reduce the accelerated tire wear and increased energy consumption caused by insufficient air pressure. system. The TPMS system communicates wirelessly through RF. Due to the strict limitation of the electromagnetic environment on the field strength, the theoretical transmission power value in the transmission module is continuously reduced. And with the increase of the volume of the vehicle, the requirements of the system for RF communication are getting hi...

AI Technical Summary

Problems solved by technology

The structure of this antenna is simple, and its disadvantage is that the radiation resistance of the small loop antenna whose circumference is much smaller than the wavelength is smaller than its loss resistance, resulting in low radiation efficiency of the small loop antenna and low gain of the small loop antenna , not suitable for transmitting antennas for long-distance communication transmitters

[0006] (4) Chip antenna: This antenna uses sheet metal as the antenna radiator, which is an electrically small antenna. Its small structure just meets the requirements of the small structure of the TPMS system transmitter. However, it has no good gain like the above-mentioned antenna. , it is possible to apply to passenger cars, but it cannot meet the requirements for trucks or large-volume vehicles

[0007] Given that current antenna solutions do not meet the requirements for a transmitter antenna for a truck or bulky vehicle TPMS system, an improved antenna is expected to meet this requirement

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