Research On Active Circuit And Antenna With High-Performance Planar Integration Technology

Miniaturized,broadband,low-cost,easy integration,and high-performance planar microwave devices are widely used in satellite communications,mobile communications,and radar applications.In this paper,based on the Substrate Integrated Waveguide(SIW)and Substrate Integrated Coaxial Line(SICL)technologies,the planar high-performance oscillators,dual linearly polarized and circularly polarized pyramidal horn antennas are carefully researched.By using SIW and SICL technologies,two novel oscillators with low phase noise and compact size are proposed,respectively.Dual linearly polarized antenna and circularly polarized antenna based on SIW multi-layered dielectric substrate are designed.In addition,a high-performance antenna array by utilizing dual linearly polarized antenna element is developed.The developed low phase noise oscillators and high-performance horn antennas have been experimentally verified and achieved good performance.The main contributions and innovations of this dissertation are listed as follows:(1)A low phase noise oscillator based on double cavity high-order mode(DCHM)resonator is proposed.The DCHM resonator is composed of two equilateral triangular single-cavity high-order mode(SCHM)resonators,and a large group delay peak is acquired by introducing an iris on the common sidewall of the two resonators.Compared with other planar structure resonators,the group delay peak has been significantly improved.The architecture of a two-stage cascaded discrete amplifier in the feedback loop to act as the gain amplifier for the loop is proposed for the first time,and applied to the design of the DCHM oscillator,thus achieving better phase noise performance.Based on the DCHM resonator,a high performance X-band oscillator is designed and implemented.Measured results show that,the proposed oscillator operates at 10.059GHz and the output power is 0.76d Bm.The phase noise of the oscillator can reach-143.1d Bc/Hz at 1MHz offset frequency,and the corresponding FOM value is 207.5d Bc/Hz.In order to reduce the size of the SIW and achieve the design goal of miniaturization of the planar oscillator,a feedback oscillator based on the circular complementary split-ring resonators(CSRR)is proposed.A pair of identical circular CSRRs are adopted and etched on the top surface of the SIW.Compared with the traditional SIW filter,the size of the filter is reduced by up to 90%,and more compact circuit size and lower insertion loss are obtained.The oscillator based on the CSRRs SIW filter operates at 5.6GHz and has outstanding phase noise performance.(2)A single-point frequency miniaturized oscillator based on SICL U-shaped resonator and a voltage-controlled oscillator(VCO)based on tunable frequency SICL resonator are proposed.The half-wavelength SICL transmission line is used as the resonant unit,which is folded along the center to form a U-shaped structure.Compared with the same frequency SIW resonator,the size of the proposed U-shape resonator is reduce by up to 80%,and more compact circuit size is realized.Moreover,a SICL-microstrip transition based on microstrip taper structure is proposed.The SICL devices can be realized with only a single-layer PCB board by using the SICL-microstrip transition.Compared with the traditional double-layered hybrid board that requires the metallized through-holes,it has the advantages of low cost and simple structure.By adjusting the gap between the parallel coupled feeder line and the U-shaped resonant unit and the length of the feeder line,the insertion loss of the SICL resonator can be reduced and the group delay peak can be increased,thereby obtaining better phase noise performance.Based on the SICL U-shaped resonator,a single-point frequency oscillator is designed and fabricated.The experimental results show that the designed oscillator operates at10.1GHz and the output power is-1.81d Bm.The phase noise of the oscillator is-138.6d Bc/Hz at 1MHz offset frequency,and the FOM value is-206.1d Bc/Hz.In order to realize the continuity of tunable oscillator,a VCO based on electrically tunable SICL resonator is proposed.By loading a varactor diode at the open end of the U-shaped resonator,the resonant center frequency of the SICL resonator can be tuned simultaneously,thus the output frequency of the VCO can be changed.The VCO based on the electrically tunable SICL resonator works at center frequency of 4.9GHz and the range of the frequency tuning is 6.49%.The designed single-point frequency oscillator and VCO have achieved excellent performance.This is the first time that passive devices based on SICL technology have been applied to the design of active devices,thus expanding the scope of application of SICL.(3)A broadband,dual linearly polarized SIW pyramidal horn antenna element and horn antenna array based on multi-layered dielectric substrate are proposed and developed.The pyramidal horn antenna element is composed of stacking multiple layers of dielectric substrates,and horn walls are formed by metallized rectangular slots,and the aperture of the horn gradually expands from the bottom layer of the substrate to the top layer of the substrate.In order to improve the polarization isolation,the differential feed network based on SICL technology is proposed.The upper and lower layer SICL differential feed networks are placed perpendicularly to each other to achieve the horizontal polarization and vertical polarization characteristics of the horn antenna,so that the transceiver system in the Ku-band can share one antenna and realize the isolation of the transceiver system.To enable the feed network to excite the waveguide mode well,the T-stubs at end of the SICL differential feed networks is proposed,thus acquiring good standing wave characteristics.Finally,the SIW pyramidal horn antenna is fabricated by using single-layered print circuit board(PCB)manufacturing process.The measurement results show that a relative standing wave bandwidth greater than 18%is achieved in both linearly polarization states,the measured maximum gain is 8.33d Bi,and the radiation efficiency is 71.8%.On the basis of the proposed horn antenna element,a 2×2 pyramid horn antenna array is proposed and fabricated.Experimental results indicate that the proposed array achieves a relative bandwidth of 15.75%,the maximum gain is 14.85d Bi,and the aperture efficiency is 73.9%.The developed dual linearly polarized horn antenna has great application value in mobile satellite communication terminals.(4)A circularly polarized pyramidal horn antenna based on SIW multi-layered dielectric substrate is proposed and developed.The proposed circularly polarized horn antenna is excited by the upper and lower layer SICL differential feed networks placed vertically to each other,so that two orthogonal waveguide modes with the same amplitude are generated at the horn radiation aperture.A 90~0coupling network based on SICL technology is proposed to achieve a 90~0phase difference between the two orthogonal waveguide modes,thus realizing the function of left-hand circularly polarized(LHCP)and right-hand circularly polarized(RHCP)of the horn antenna.In addition,in order to make the phase distribution of the horn aperture more uniform,a cross metal strip structure at the center of the horn aperture is proposed,thereby increasing the gain of the horn antenna and improving the radiation efficiency.The reflection coefficient and axial ratio(AR)characteristics of the horn antenna,as well as the design processes,amplitude and phase balance of the feed network are analyzed detailedly.The final measurement results show that the proposed circularly polarized pyramidal horn antenna works at center frequency 12.5GHz,the measured gain is 8.4d Bi,the relative standing wave and axial ratio(AR)bandwidth are approximately 24%and 5%,respectively.And the radiation aperture efficiency is as high as 78.5%.The developed circularly polarized pyramidal horn antenna can be applied in the field of satellite communications.