| Microwave and millimeter wave circuits and devices have undergone several generations of development,and the current trend toward planarization and integration is becoming more and more intense.With the introduction of substrate integration technology,similar metal waveguide component circuits have been successfully fabricated on flat circuit boards at home and abroad in recent years,called substrate integrated waveguide（SIW）,and the corresponding circuit is called substrate integrated circuits（SIC）,the integrated waveguide devices and circuits are currently the hotspots of international research,and new research results are reported endlessly.Substrate integration technology is also constantly being pushed forward,because SIW is usually processed on a printed circuit board（PCB）.Under this concept,a unique half mode substrate integrated waveguide（HMSIW）is proposed.The application of this structure greatly enriches the hybrid integration technology.When communication and radar systems are constantly updated and higher frequency circuits and devices are required,since the metal loss of such devices as SIW will increase with the increase in frequency,it will become a bottleneck restricting its application（as we all know,when the operating frequency continues to rise metal loss will become the main work problem.The higher the frequency is,the more serious the problem is.）It is very urgent to develop new substrate integrated circuits with low metal loss at higher frequencies.An integrated technology based on non-radiative dielectric waveguides is proposed which is called substrate integrated non-radiative dielectric waveguide（SINRD）,which can provide strong technical support for communication and radar systems above 60GHz,and can greatly enhance the level and level of these systems.The millimeter wave ridge-gap waveguide realized by using a multilayer structure and making metal through holes on the PCB is another deformable substrate integration technology,which uses the concept of artificial magnetic conductors to achieve a new type of efficient and reliable transmission waveguide.In addition,there are other hybrid integrated waveguide structures,such as substrate integrated coaxial lines.This thesis conducts a more detailed study on these extended substrate integration technologies,and designs some microwave and millimeter wave circuits,and explores the application of these technologies in passive circuits,which is useful for wireless networks,microwave imaging,biomedicine,and environmental protection.In many fields such as detection and radar remote sensing,it has important research value and long-term scientific significance.In this paper,the main research contents and contributions of these expanded substrate integrated waveguide technologies are as follows:1.The SINRD waveguide manufactured directly on the PCB or metalized dielectric layer has excellent performance of simplifying the manufacturing process and minimizing mechanical errors,but this circuit structure is more difficult to excite.This paper proposes and studies two SINRD waveguide excitations circuit,one is to use the microstrip line to the slot line transition structure,and then use the field similarity between the slot line quasi-TEM wave main mode and the SINRD waveguide LSM11 main mode,use the slot line to excite the PCB type SINRD waveguide new feed structure.By using a multilayer structure,the circuit is composed of a two-layer Arlon TC600 PCB,and the transition circuit from the microstrip structure to the slot line can be directly soldered on a thinner board.Next,the required operating mode LSM11 mode can be excited near the center of the SINRD waveguide dielectric strip.This slot line to SINRD waveguide configuration can achieve a wider bandwidth and a high degree of integration.The other is the transition from coplanar waveguide（CPW）to a SINRD waveguide-based structure,which provides an effective interconnection for compact and flexible integration of planar CPW-based devices and SINRD waveguide circuits.The research found that the simulation results are in good agreement with the actual measurement results,which proves that the SINRD waveguide based on ordinary PCB development has broad application prospects in the field of millimeter wave hybrid integrated systems.2.Printed ridge gap waveguide（PRGW）is a new type of millimeter wave waveguide structure.Based on the parallel plate waveguide,this technology uses an artificial magnetic conductor（AMC）periodic array structure and uses air as the propagation medium,which allows the structure to largely avoid the loss caused by dielectric materials.This millimeter wave waveguide structure is mixed with a multilayer planar circuit structure.The AMC part is formed by making a large number of metal vias on the PCB with similar substrate integration technology,which has both in-phase reflection characteristics for plane waves and specific frequency bands.The electromagnetic bandgap characteristics of this technology can break through the limit of traditional microwave and millimeter wave device structure design and improve the overall performance of microwave and millimeter wave devices.For millimeter wave communication applications,this paper studies this PRGW,and proposes a low-loss Ka-band coupled resonator band-pass filter based on PRGW technology.PRGW is used to allow electromagnetic waves to propagate in the air gap to avoid dielectric loss and improve transmission performance,and is suitable for millimeter wave applications.The band-pass filter is implemented using two transmission zeros,which can be easily obtained by adjusting the length of the stubs of the two T-shaped stub loaded resonators.From its analog frequency response point of view,the insertion loss of the filter is 0.8 d B,the return loss during the pass band is less than-20 d B,and the cut-off frequency has high selectivity,proving that PRGW is an excellent millimeter wave hybrid integrated waveguide structure.3.HMSIW technology is a unique new technology under the framework of substrate integration technology.Compared with the complete SIW structure,half of the structure of the HMSIW circuit can be cancelled,so the structure is more compact;at the same time,because the structure is semi-open,and It can be used in the coupling circuit structure to develop a new type of half-mode structure circuit.This paper proposes a coupler based on HMSIW,which connects the equivalent magnetic wall of two HMSIW transmission lines with a metal spur line to achieve strong coupling.And the 6d B and 3d B directional couplers have been realized.In order to obtain a wider frequency band when designing the power splitter,an inductive metal through hole was added at the junction of the microstrip gradient line and the SIW to optimize the transition.On this basis,a microwave six-port circuit is designed using a 3d B directional coupler and power splitter,which can be used in wireless communication antennas and various radio-frequency equipments. |
