Design Of Digital Frequency-hopping Filter Based On LTCC

The rapid development of communication technology has made spectrum resources increasingly intense,and improving the utilization of spectrum resources is imminent.Frequency-hopping communication technology can continuously switch working frequency points within a frequency band,which improves the spectrum utilization rate and has the advantages of anti-interference and high concealment.In the frequency-hopping communication system,the frequency-hopping filter is very important.The performance of the frequency-hopping filter determines the performance of the entire system.Today,with the electronic technology rapidly develops,all kinds of electronic products are developing in a smaller and lighter direction.Therefore,it is of great significance to study the miniaturization of frequency-hopping filters.In this paper,a digital frequency-hopping filter with operating frequency range of225MHz⁵12MHz is designed,and the miniaturization of the device is realized by combining the low-temperature co-firing ceramics?LTCC?process.This frequency-hopping filter can be used as a preselected filter for the high-frequency front-end of various radio receivers,and also can be used for excitation level input of transmitters.First of all,the transformation principle of low-pass prototype filter to the coupled resonance band-pass filter is deduced,and the frequency hopping characteristics of the LC band-pass filter are analyzed in conjunction with simulation tools,and various parameter values are obtained through optimization and circuit structure conversion.And then the modeling and simulation method of LTCC embedded inductance is studied,and the influence of structural parameters such as dielectric layer thickness,conductor width,conductor thickness,and coil area on the electrical performance of embedded inductance is analyzed.Based on this,the inductance of frequency-hopping filter is designed as a three-dimensional spiral inductance with excellent electrical performance,which is beneficial to the miniaturization design of the frequency-hopping filter.Secondly,the principle of calculating the value of the capacitor array in the frequency hopping filter is studied,and a simulation circuit of the capacitor array is built in ADS,This circuit can simulate the working condition of 12 capacitor arrays,and all the combined values of capacitors can be traversed according to the given 12 capacitor values.Then the test board is designed by using Single-Chip Microcomputer and PIN driver chip,and the sample of frequency-hopping filter is assembled and tested.The test results can cover the entire225MHz⁵12MHz frequency band.The insertion loss is within 9dB,the voltage standing wave ratio is within 2,and the suppression atf₀?35MHz is greater than 20dB,and the external size is 22mm×18mm.Finally,the insertion loss in the test results is analyzed,the difference between single-channel capacitance and double-channel capacitance in insertion loss is simulated,and an improved method is proposed to reduce the insertion loss.