Research On Millimeter-wave Waveguide Multi-way Power Divider/Combiners

In recent years, the millimeter-wave techniques have received great attention in both fields of civil and military application. For the communication applications, millimeter-wave communication has complied with the trend that the operating frequency is getting higher; for the military applications, millimeter-wave is an important technical solution of information countermeasure; even for the medical applications, it also has great potential. And power amplifier is one of the key elements of millimeter-wave communication systems. But as the operating frequency increases, the size and power handling capability of a single device are reduced, which may not satisfy the requirement of an existing system. To achieve enough output power, it is practical to combine the output power of multiple devices. So nowadays millimeter-wave power divider/combiners have been studied widely.The existing solution of techniques for millimeter-wave power dividing/combining can be concluded into five ways: the corporate structure(or binary tree structure), chain combining structure, spatial combining structure, quasi-optical power combining and radial combining structure. Compared with other solutions, the radial power divider has the advantages in the ability of dividing/ combining N-way signals in a single level, also, the amplitude and phase imbalance performance is excellent. This thesis mainly focus on developing an isolated, miniaturized radial power divider/combiner, also, the designing and fabrication approach of a Magic-T with coplanar arms has been improved, the major tasks achievements of this thesis are listed as below:1. A rectangular waveguide-to-circular waveguide mode converter based on E-T divider network has been designed out. This structure has taken advantage of the features that the electric field lines of the TE01 mode in the circular waveguide distributed assumes the circular closed lines, by designing the E-T divider network and join it with the converter section, the TE10 mode in the rectangular waveguide is converted into the TE01 mode in the circular waveguide. Compared with the conventional structure, this mode converter has advantages in size and mode purity. This thesis has introduced the principle and designing approach, finally, a back-to-back structure of this Ka-band mode converter has been fabricated and tested, the experimental result agree well with the simulation result.1. An isolated twenty-way radial power divider/combiner based on the mode converter we discussed above has been carried out. By using the TE01 mode converter, the requirement that both input and output ports should be in rectangular waveguide form is satisfied,moreover, the size has been reduced greatly. By inserting resistive septum between the output ports, the ports matching and isolation is improved. This thesis has discussed the operating principle and realization approach, finally, this radial power divider is manufactured and tested, the experimental result agree well with the simulation result, which presents excellent features.3. A Magic-T with coplanar arms based on ridge-waveguide has been developed. This structure is on the base of an existing method: the Magic-T with coplanar arms based on waveguide-to-microstrip probe structure. By replacing the waveguide-to-microstrip probe structure with ridge-waveguide coupling structure, the power handling capability is improved and the fabrication is easier. Accomplishing the designing and simulation, a prototype of the ridge-waveguide Magic-T is carried out and measured, finally the measured results are analyzed and concluded.