The Study Of Ka/X Band Integrated Up/Down Converter Module

In order to meet the increasing demand for ultra-high speed communication, wireless researchers worldwide have been expanding the field of study to millimeter-waveband or even wavebands of Terahertz. Millimeter wave up/down converter module, an important component of the millimeter wave front end, has a pivotal role for the system development.This research provided an in-depth study on Ka-band millimeter wave up/down converter module, and established the entire process for up/down converter development. This paper reviewed the state-of-art progresses on the development of the translator module and mixers in millimeter wave system, and explored the future directions in this field. Meanwhile, this paper specifically illustrated the structure and key performance indices of mixers, amplifiers and PLLs, laid the theoretical foundation for the system design.In this paper, the design of the module was divided into four key components:(1) LO unit which provided the basic frequency signal for the module;(2) up-converter unit which up-converts the X-band IF signals to the Ka-band;(3) down-converter unit which down convert the Ka-band RF signals to the X-band; and(4) power unit which to power the whole module. This division of the structure makes the module’s function clear and definite, easy to design and maintain. The paper introduced the whole flow for designing the scheme for each unit, including indexes decomposition, devices selection and key circuit design.After two rounds of design and fabrication, the final product delivered is of 80mm×50mm×17mm in size. It achieved not only high integration but also high performance. The up-converter channel gain was about 37 dB, the spurious suppression was greater than 55 dBc, and the channel power flatness was 1.06dB; the down-converter channel gain was about-7dB, the spurious suppression was greater than 60 dBc, and the channel power flatness was 2.38 dB. Cascade tests of both up-converter and down-converter channel showed channel power flatness is 2.2dB, exceeding the required 3dB.In addition, this paper analyzed and provided practical solutions to many issues encountered in the design and debugging phases. All of these could be helpful for other designers to avoid the similar problems in the up/down converter design.Overall, frequency translator module has a key role in millimeter wave communication system, such as commercial communications and military radar. It is a promising and for future research and investigation. The paper provides a practical and insightful view into the up/down converter design.