Study On Terahertz Filter Circuit

Filter is employed to extract specified band in an electronic system. With thedeepening of research on terahertz technology, there is urgent need forhigh-performance terahertz filter. It is necessary to find out the way of performingaccurate designing and fabricating.Proper filter structures were selected in this thesis by inspecting domestic andforeign developments.380GHz iris inductive window coupled waveguide filters and220GHz waveguide filter were designed and fabricated by utilizing MEMS procedure(silicon bulk micromachining technology) as well as ultra-precision machineryprocessing technology, respectively. Measurement for380GHz filter was finished. Themain topics of this thesis include:1. design and fabrication of380GHz iris inductive window coupled rectangularwaveguide filters. Achievements of high-performance terahertz filter beyond100GHzare less reported, especially beyond300GHz. The developing of380GHz filterpresented in this thesis is of considerable difficulty and creativity.Iris inductive window coupled structure was utilized to design380GHz filter. Thefabrication was executed by accurate MEMS procedure (silicon bulk micromachiningtechnology). Measurement was performed using500GHz VNA system, whose resultindicates a success. In the case of two-order filter, the measured center frequency is384.89GHz with3dB bandwidth of15.08GHz (3.92%), the rejection of stopband isabout30dB at2.5times of bandwidth, minimum insertion loss is2.7dB, averageinsertion loss is about3dB, return loss is about10dB. The measured result shows goodagreement with simulated one. The project is successfully completed and furtherimprovement is made by employing H-plane-offset inductive windows coupledstructure.2. design of220GHz rectangular waveguide filters. Achievements of220GHzbandpass filters are also less reported at present. The absence is partly filled up by ourwork on220GHz filter presented in this thesis. Iris inductive windows coupledstructure and corrugated structure were selected in the design of220GHz filters. The design of iris inductive windows coupled structure was fabricated by ultra-precisionmachining technology, and integrated with flange structure. The designed centerfrequency is218.7GHz, the3dB bandwidth is10.2GHz (4.66%), return loss is betterthan10dB, and the rejection of stopband is better than25dB. The analysis and design ofcorrugated structure were fulfilled. Simulation result indicates that the center frequencyis219.35GHz with the3dB bandwidth of17.70GHz (8.07%), return loss is better than17.45dB, the rectangular coefficient is outstanding with the rejection of stopband betterthan80dB at offset of one bandwidth by center frequency.Terahertz filters at380GHz and220GHz were successfully designed andfabricated in this thesis by analyzing and studying design theory and utilizing availablefabrication procedure. It is beneficial to follow-up study work of terahertz passivecomponents, and is practical to terahertz transceivers.