The Design And Realization Of Transmitter Module In S-band Non-liner Junction Detector

S band non-liner junction detector is another use of harmonic radar. It uses harmonic radiationcharacteristic of non-linear junction to detect the non-linear junction target, through transmittingfundamental wave and receiving harmonic waves or combination waves from the target’sre-radiation. Common targets can not re-radiate harmonic or combination waves under theincidence of electromagnetic wave except non-linear junction targets, such as semi-conductorjunction or two dissimilar metals. Based on this advantage, non-liner junction detector has bettereffective ability of inhibiting clutters than other detectors. According to this character of non-linearjunction re-radiation, non-liner junction detector is widely used in national defense, public security,counterreconnaissance, sweep, airports and ports security. In recent years, with the size of electronicproducts getting smaller and conventional detectors has the blind zone to detect the mobile phoneand USB flash disk, the inchoate detectors fall out of use. There expect a new smaller, portable andpowerful detector to meet those market demands. In this context, we do some research on S bandnonlinear junction detector, and put forward the transmitter module design and production.The design and realization of transmitter module in S-band non-liner junction detector isdiscussed in this paper. Through to comparing and analyzing some existing transmitters topologystructure, we finally used the project based on phase locked loop of the direct thevariable-frequency transmitter. This transmitter has simple structure, high hardware integration andeasy to miniaturize the launch module. The key content of the paper is to design and realize threetransmitter modules, including phase-locked frequency source, power amplifier andcrossing-coupled cavity filter. When it comes to phase-locked frequency source, this paper briefpresents the technology indexes of phase-locked frequency synthesized technology, analyzes thebasic principle, stability and phase noise performance of phase-locked loop. Though the simulationsoftware which is provided by ADI company, we design the loop filter and registers of ADF4350.We use the AVR single processor ATMEGA8 to write the program to PLL chip ADF4350, and thendebug the program, finally output the 3.36GHz. The paper gives the main circuit design and testresults. For the power amplifier, this text summarizes the technology indexes and design method ofpower amplifier, make foucs on designing the match circuits, and detailed presentes the process ofusing AVAGO company power amplifier chip ALM-42316 design and PCB production, finallygives the test results and analyze the test results, finally gives the test results and analyze the testresults. For the filter, this paper researches the design methods of crossing-coupled cavity filter.Though MATLAB simulation software, we extract coupling matrix and the coupling coefficient.According to the requirements in the coupling factor and the index, we establish crossing-coupled cavity filter model in HFSS and simulation optimization, finally get the filter which is meet index.At last, we test the whole transmitter module. By the test results, we find the transmittermodules meet the indexes requirement. The gain of S-band non-liner junction detector transmittermodules is 28dB, the output power is larger than 26dBm. This results show that this transmittermodules can meet the indexes requirement. At the same time, the analysis of EMI and EMC aretaken into account.