Study on a power combiner using an oversized-waveguide resonator at short millimeter wavelengths.

该研究项目计划利用空间功率组合技术开发一种在短毫米波频率下工作的高功率固态振荡器。为此，在谐振器中加入了包含固态器件的TE_<10>模式波导阵列的超大（超模）波导谐振子已被用于谐波模式器件的有效功率组合。在过模波导谐振器中，固态器件，在我们的例子中是Gunn二极管，在基频上同步振荡，然后产生二次谐波。来自多个二极管的谐波在同一谐振腔内相干地和空间地组合在一起，因此即使在90 GHz以上的高频下也可以获得更高的功率。理论和实验结果如下：1。在89GHz ~ 99ghz的谐波频率范围内，首次实现了15个Gunn二极管的相干功率组合。采用5x3波导的Gunn二极管阵列，在94 GHz频段的功率组合效率约为67%，输出功率为0.25 W（连续波）。这些结果表明，用于谐波模器件空间功率组合的超模波导谐振腔对于产生强短毫米波是非常有用的。为了实现谐振腔的设计，本文从理论上推导出了过模波导谐振子的等效电路，并进行了实验验证。证实了一种能在基频和次谐波频率上对谐振器进行调谐的片层背短路的有效性。结果表明，功率组合效率主要取决于二极管射频特性的均匀性。

This research project has been planed to develop a high power solid-state oscillator operating at short-millimeter wave frequencies utilizing a spatial power combining technique. For this purpose, an oversized (overmoded) -waveguide harmonic oscillator which incorporates an array of TE_<10> mode waveguides containing solid state devices into the resonator, have been used for an efficient power combining of harmonic-mode devices. In the overmoded-waveguide resonator, solid state devices, in our case Gunn diodes, oscillate at the fundamental frequency in phase and then generate the second harmonic waves. The harmonic waves from a number of the diodes are combined coherently and spatially in the same resonator, so that higher power can be attained even at high frequencies above 90 GHz. The theoretical and experimental results are as follows,1.Coherent power combining of fifteen Gunn diodes has been demonstrated for the first time at the harmonic frequencies between 89GHz and 99 GHz.2.A power combining efficiency of about 67% and an output power of 0.25 W (continuous wave) at 94 GHz band has been achieved with a 5x3 waveguide Gunn diode array. These results indicate that the overmoded waveguide resonator for spatial power combining of harmonic-mode devices is very useful for producing intense short-millimeter waves.3.In order to design the resonator, the equivalent circuit for the overmoded waveguide harmonic oscillator has been developed theoretically and verified experimentally.4.Effectiveness of a lamellar back short which can tune the resonator at both the fundamental and the second harmonic frequencies has been confirmed.5.It has been found that the power combining efficiency has been determined mainly by uniformity of rf-characteristics of the diodes.