Passive Component Design Based On Substrate Integrated Coaxial Line

With the continuous development of wireless communication technology,the requirements of communication system for devices are higher and higher.How to reduce the volume,weight and cost of microwave components,but also maintain the excellent characteristics of low loss,high power capacity and so on,has become a new challenge for researchers.Microstrip line is widely used because of its low cost and small size,but its unshielded structure has the problems of crosstalk and scattering.The substrate integrated waveguide(SIW)inherits the advantages of waveguide and microstrip line.It has the advantages of high power capacity and easy processing,but it can not propagate TEM mode and is not suitable for wide-band applications.The substrate integrated coaxial line(SICL)inherits the SIW shielding structure,but its size is smaller than SIW structure.It is a kind of planar coaxial line,with the advantages of small loss and easy processing.At the same time,SICL structure propagates TEM mode without dispersion,which is very suitable for wide-band system application and easy to integrate with other planar circuits.Therefore,SICL has great research value.Firstly,this paper introduces the basic theory of substrate integrated coaxial line,and according to the characteristics of substrate integrated coaxial line,a passive circuit device based on substrate integrated coaxial line is designed.The main work of this paper is as follows:First,based on the chip integrated coaxial line,a dual band-pass filter is designed by simply installing two parallel coupling lines on a ring resonator,which has the characteristics of simple structure,small volume and two pairs of degenerate resonant modes.The filter has simple structure and good performance in two working frequency bands.Secondly,using the characteristics of large bandwidth and small loss of the substrate integrated coaxial single-mode,a low loss broadband band-pass type interdigital filter is designed.Similar to the traditional hairpin filter,the U-shaped resonator is used as the resonant unit.But it has only two resonance units,and through cross coupling,a band-pass filter with a relative bandwidth of 3d B of 60% is obtained,which has low internal loss of working bandwidth and good performance.Thirdly,a stop band filter power divider is designed based on the characteristics of large bandwidth and small loss of substrate integrated coaxial single mode.In the traditional power divider,a high impedance line of ?/2 wavelength is used to connect the left and right sides,and the power divider will form a small stopband at the center frequency.By controlling the length of the connecting wire,the center frequency of the stopband can be adjusted at will.By increasing the number of connecting wires,the bandwidth of stopband can be increased.Based on the stop band filter power divider,a dual band-pass filter power divider is formed by paralleling the open branch lines.