Research And Design Of Substrate Integrated Waveguide Field-shifted Isolator Assembly

The SIW structure has the advantages of conventional waveguides and microstrip-type transmission lines,ie,low radiation,low insertion loss,high value,high power capacity,miniaturization,and ease of connection.The paper analyzes the advantages and disadvantages of air-filled substrate integrated waveguides.A SIW transmission line incorporating a magnetic cylinder was designed.Based on the gyromagnetic properties of ferrites,two X-band substrate-integrated waveguide field-shift type isolators with the same structure and different frequency bands are designed.The isolator has low loss,small size and easy integration.And the structure of the ferrite in the traditional field-shifting isolator was explored and a ferromagnetic Ku-band narrow-band isolator with a non-continuous periodic cylindrical structure was designed.A new type of transmission line incorporating a magnetic cylinder has been designed.The transmission line has improved insertion loss and return loss by 15%.An air-filled substrate integrated waveguide,one of the research hotspots in recent years,has been subjected to loss and power analysis.The air-filled substrate integrated waveguide loss is much lower than the dielectric fill and the average power handling capability is also higher than the dielectric-filled substrate integrated waveguide.The use of an isolator sometimes requires the use of a filter.In this paper,a generalized Chebyshev X-band narrowband filter and isolator have been designed to form an isolator assembly.The filter is based on an air-filled substrate-integrated waveguide and uses a sixth-order resonator to implement a filter along the centerline and up and down symmetric structures.The center frequency is 11.66679 GHz,the bandpass is 11.663 to 11676,and the bandwidth is 13.5M and the square rate is 20 dB.:2.14.The outstanding advantages of the filter are the high squareness ratio and the low relative bandwidth.After introducing the principle and characteristics of various microwave ferrite isolators,we designed two field-integrated waveguides with the same structure.The center frequency of the field-shifted isolator was 10.6GHz,and the isolation bandwidth of 20 dB was 78 MHz field-shift isolation.The device has an insertion loss of less than 1dB and a maximum isolation of 40 dB.The effects of saturation magnetization of ferrite materials and applied bias magnetic field on device performance were studied.The influence of distance between the ferrite and the nearby metal cylinder on the performance of the device was studied,as well as the influence of other device dimensions on the field-shifted isolator device.An anisotropic ferrite SIW field-shifting isolator was also designed.The ferrite uses a non-continuous cyclic cylindrical structure that resembles the SIW metal via structure.The ferrite diameter and the gap between the ferrite cylinders were analyzed.The Ku-band narrow-band field-shifting isolator was finally realized.The structural innovation of the field-configured isolator with traditional structure has reduced the volume of ferrite,and a new type of field-shifting isolator has been realized.The isolated point frequency is 13.1GHz,the isolation is 34 dB,and the insertion loss is 1.5dB.The Auto CAD drawing of the three field-shifted isolators was designed.