Research On Wideband Frequency Conversion Components In Millimeter Wave Spectrum Analyzer

The spectrum analyzer plays an important role in the testing of microwave circuits and systems.With the development of millimeter-wave technology,millimeter-wave spectrum analyzers have received widespread attention,which are characterized by higher frequency ranges and wider analysis bandwidths.The millimeter-wave spectrum analyzer currently used in China is mainly imported from Keysight,R & S and other foreign companies.In order to master the core technology of the millimeter wave spectrum analyzer,this paper studies the frequency conversion component of the millimeter-wave spectrum analyzer RF front-end,aimed to develop a broadband millimeter-wave frequency conversion component with high image frequency rejection and local oscillator harmonic suppression.In order to facilitate the selection of the mixer and the design of the filter,the millimeter-wave frequency conversion component is divided into four channels according to frequency,and each channel is designed separately.The main work of this article is as follows:First,for 22GHz?40GHz frequency conversion components,a cascaded open-resonance ring(SSR)band-rejection filter and a substrate-integrated waveguide with defective ground structures(SIW-DGS)filter are designed as RF and local oscillator filters,respectively.A bare chip packaged mixer is selected to implement a planar integrated circuit frequency conversion component.The test results show that the frequency conversion performance is good and it has the functions of image frequency rejection and local oscillator harmonic suppression.Next,for 40GHz?52GHz and 52GHz?67GHz frequency conversion components,rectangular waveguide high-pass filters and symmetrical double-ridged waveguide band-pass filters are designed as RF and local oscillator filters,respectively.A module-packaged mixer is selected to realize the waveguide three-dimensional circuit-type frequency conversion component,which has a high image rejection ratio of more than 90 d Bc and low loss to the local oscillator filter.Finally,for the 67GHz?76GHz frequency conversion component,the WR12 standard waveguide port is used to be the RF port,and a waveguide-SIW vertical adapter is designed to realize the connection between the waveguide and the planar circuit.Rectangular waveguide high-pass filters and symmetrical double-ridged waveguide band-pass filters were designed as RF and local oscillator filters,respectively.The selected bare chip packaged mixer is modularized to realize a waveguide three-dimensional circuit-type frequency conversion component.The test results show that the component frequency conversion has good frequency conversion performance and harmonic suppression function.