Research On High-performance And Wide-band Delay Line

In recent years,the technology of wideband phased array radar has developed rapidly,and has shown excellent performance in the military field.The implement of wideband signal requires that phased radar must employ instantaneous wideband signal,which results in the replacing of phase shifter with true time delay line at the subarray level in the phased array systems.As the key component of the RF front subarrays in the phased array radar,the delay module often integrates many functions,including long delay,receiving,transmitting and amplification,which mostly implemented in the form of hybrid integrated circuit.The performance of the delay module determines the performance of the phased array radar directly.Based on the mature thin film circuit technology and hybrid integrated circuit design,this paper aims at the research and design of high performance true time delay line.Based on that,an x-band six-bit digital-controlled delay module with receiving,transmitting and amplifing function has been designed.The main contents of this paper include the following two parts:1.Based on the processing technology of alumina ceramic thin film circuit and with the help of three-dmen electromagnetic simulation software HFSS,the transmission characteristics of the meandering microstrip delay line and of the meandering coplanar waveguide delay line has been analyzed.The structures of the circuit hve been analyzed too.On this basis,the meandering microstrip delay line units and the meandering coplanar delau line units for 1?,2?,4? and 8? are carefully designed.Finally,the simulation results of the 8? meandering microstrip delay line unit achieves that the phase shift accuracy is better than 20 degrees,the maximum standing wave coefficient is less than 1.2,and the insertion loss is less than 1.5,in frequence range of 8.8GHz to 10 GHz.The 8? meandering coplanar waveguide delay line unit has achieved the phase shift precision of 2 degrees,the maximum standing wave coefficient less than 1.1,and the insertion loss less than 3.2dB.Compared with other delay line in the same frequency band,the two kinds of delay lines have the advantages of high delay accuracy and good phase linearity,which lay the foundation for the design of the delay line module.At the same time,aiming at the influence of temperature change on phase shift,a temperature compensation circuit has been designed to compensate the phase shift in the delay unit.2.An X-band six-bit digital-controlled true time delay transmitting-receiving module has been designed and machined.According to the technical index of the module,the whole scheme of the module and circuit have been carefully designed.The units of the delay module adopt the tortuous coplanar waveguide delay line,which contain six delay units.The step volume is 1?,and there are 63 delayed states.Finally,the delay accuracy of the 1?,2?,4?,8?,16? and 32? units in the working frequency band is better than 7 degrees,the phase linearity is less than 10 degrees,the gain is 14 dB,and the gain flatness is less than 1.6dB.The delay line and the delay module designed in our research make full use of the planar circuit processing technology,and have the advantages of high performance,low cost,essy integration and simple structure,which can meet the needs of wideband phased array system for high-perhormance delay module.