Search And Rescue Radar Transponders Design And Implementation

Search and rescue radar transponder(SART)is a key device used to indicate the position of vessels and survivors fell in distress,in Global Maritime Safety System(GMDSS).SART immediately will respond to 12 successive pulses,when it receives a pulse sent form navigational radar of rescue vessels.People on the rescue vessel can clearly know the direction and location information,in convenient to rapidly organizing rescue and reducing loss of life and property.Aboard,related research and manufacturing work have been started for a long time.At present,SART sold well are almost manufactured by US or EU.In comparison,there is less research in China,and technological is backwardness.In this paper,a highly integrated low-power SART is designed and implemented after studying basic theory.In transmitter,HMC511 generating a 9.2GHz~9.5GHz microwave signal,which is amplified to 30 dBm by microwave high power amplifier HMC590.Transmitter has simple and compact structure,but is high stability.Microwave low-noise transistor NE3210S01 is used to design low noise amplifier(LNA)of receiver using.By building Circuit model,simulating and optimizing parameters in ADS,measured gain of LAN real circuit reaches up to about 11 dB.Sensitivity of the detector circuit is up to-45 dBm by using logarithmic detector chip AD8317.To reduce noise out of band,parallel coupled microstrip filter is inserted between the detector and the LNA.Transceiver circuit is isolated by circulator,and isolation is greater than 20 dB.Waveguide slot antenna with vertical beamwidth ±12.5°,and average gain in the horizontal direction 3.5dBi,is use to receive and send signal.SART can choose to work in the transmitter mode,the receiver mode and operating mode for easy testing and inspection.Test results show that,transmit power is 30 dBm and receiver sensitivity is more than-50 dBm,which are both higher than the international standard.The response delay is less than 0.5uS.Using 7.2V/13000 mAh lithium battery,standby time is 123 hours,SART can continuous working time 54 h and work standby 129 h.So,SART designed in this paper has compact structure,high stability,and superior performance.