The Design And Implementation Of Multifunctional Frequency Conversion Chip

With the development of So C and integration technology, RF circuits are now largely designed in an integrated way and are evolving from wireless transceiver components to the MMIC. This transition means not only a big change in system size, but also a leap from discrete components to mixed signal system with more and more functions integrated. Amid the large amount of discrete components in the T/R module, power amplifiers and mixers play key roles, directly impacting the sensitivity and minimum signal-to-noise ratio.This thesis designed an MMIC chip, which is used in the phased array radar system, and studied its testing method. The main part of chip was a passive double balanced mixer. The LO port the mixer is integrated with 20 d B-gain driver amplifiers, while the RF port integrated with a 16 d B-gain bidirectional amplifier. The multifunctional chip could meet the requirements of up and down frequency conversion. After careful research of the basic theory of RF circuit design, layout simulation of discrete components of the chip was conducted with the ADS to make sure that the performance met the requirements, so as to integrate them to complete the frequency conversion chip. Systematic simulation results showed that the system could provide 8d B gain with a good flatness of frequency band, the return loss was better than-10 d B, and the isolations between ports were also of good performance.The designed layout was successfully taped out using the ED 0.25μm PHEMT process line. The chip got through bare-chip probe test with Cascade’s probe platform and Agilent’s 4 ports vector network analyzer. Comparing the test results with simulation, although some parameters were of few deviation, the chip satisfied the requirements and met the expectations in performance. Then the chip was redesigned to get a compacter size and was manufactured and tested again. Finally, test showed that the compression of the chip incurred some deteriorationg in performance, but the redesign was acceptible in practicle application and the design objective was mainly accomplished.