Research On Millimeter Wave Sweep Source And Gap Waveguide Antenna

Millimeter wave has the characteristics of wide bandwidth,short wavelength,narrow beam,high resolution,good directivity,and high reliability.It can work all time in complex environments such as rain,fog,and cloudy,and has the advantages of natural propagation characteristics.As an important propagation carrier of radar and communication systems,millimeter wave technology has been widely used.Under the need of higher speed and more connections in the 5G era,millimeter wave technology has a large amount of available bandwidth and high antenna gain,and supports ultra-high-speed transmission rates,and the beam is narrow,flexible and controllable,and can connect a large number of Equipment.Thus it can be seen that millimeter wave transmission and reception detection technology has become an important part of 5G communication,and even one of the focus of global information technology competition.In this paper,the millimeter wave sweep source and gap waveguide antenna is studied,with a cascade of the two devices that a complete radio frequency front-end transceiver system can be achieved.On the one hand,the millimeter wave sweep source can produce high-quality millimeter wave signals and emit signals to the target;on the other hand,it combines the receiving down-mixing module to realize the detection of the target reflected signal.The antenna is the end of the electromagnetic wave signal transmission and the front end of the reception.It is an essential part of the millimeter wave communication and radar system.This article mainly studies the RF front-end system which made up of the sweep source and transceiver antenna.The research contents are as follows:1.Research of millimeter wave sweep source technology.First of all,the paper introduces the technical principle and sweep source' application,and then expounds four common principle of microwave frequency synthesis technology and analyzes its technical characteristics,and finally introduces the sweep source's common technical indicators,analyzing its main influencing factors to provide a theoretical basis for sweep source design in the following part.2.Research on the structure and theory of gap waveguides.First,the basic structure and classification of gap waveguides are introduced.Then,the principle of high-impedance surface formation and the technical characteristics of pin-type structures are analyzed.Finally,the groove gap waveguide transmission theory is mainly introduced,which provides theoretical support for the design of groove gap waveguide antennas.3.Researched and designed a high-performance millimeter-wave sweep source device with low phase noise,low spurs,and agile frequency conversion.Through the comprehensive use of mixing,frequency division,frequency multiplier,amplification,filtering,PLL technology and DDS digital synthesis technology,the bandwidth of 5GHz was finally achieved in Ka band,with multi-channel millimeter wave signal output,the minimum switching time between the frequency of the device is 7.5ns;the spurious suppression is greater than-45 d Bc;the typical value of power flatness is better than ± 1.5d B;the output power is greater than 12 d Bm;and can flexibly configure the power amplifier to achieve power amplification.4.The double-layer groove gap waveguide transmission structure and high-gain horn antenna were researched and designed.Compared with the traditional single-layer groove gap waveguide transmission structure,the double-layer groove gap waveguide transmission structure reduces the nail height to half of the original one,which is more conducive to be manufactured.The high-gain horn antenna design based on a double-layer groove gap waveguide transmission structure has a bandwidth of 41%(26.5-40GHz)and a maximum gain of 13.3d Bi in the entire frequency band.In order to further improve the impedance matching and radiation characteristics,a trapezoidal dielectric plate was subsequently added in the gap between the double-layer nail plates,so that S11 is less than-12.5d B,the gain is 12-15 d Bi,and the front-to-back ratio is greater than 21 d B,in the entire Ka band.The groove gap waveguide horn antenna gain and front-toback ratio are better than current antennas in the same frequency band.