Research On Noise Figure Measurement And Radio Frequency Amplifier

This article introduces the method of extending noise figure meter HP 8970A measurement frequency range. Accord to the demand of noise figure measurement of our laboratory, a low VSWR, low noise block down converter used for extending noise figure meter HP 8970A measurement frequency range from 10MHz～1500MHz to 1500MHz～2200MHz is designed, this includes core frequency band for 3G. The performance of the new and old measurement system is compared; a 10dB passive attenuator is used to validate the new measurement system. Right now, existing noise figure analyzer can only make corrections for losses before DUT (Device Under Test) and after DUT, this article advances a new situation which also needs loss corrections. When a lossy component which is included in the calibration loop is not connected after the DUT in the measurement step, corrections are also needed. The combinations of this new situation and the two existent cases and their combinations form self-contained loss correction method. According to the theory of noise figure measurement, derivation of loss correction formulae for all kinds of situations is presented and effects of extra losses on measurement uncertainties are studied in detail. This article also presents the design of a 1.9GHz balanced low noise amplifier. ADS is used to analyze and simulate the circuit, and noise figure of the low noise amplifier is successfully measured using our low noise block down converter. The circuit schematic and PCB of the low noise amplifier are presented in the appendix. At last, this article describes the design and implement of a GSM amplifier module which includes an 885~915MHz low noise amplifier and a 930~960MHz 8W power amplifier. System schematic, PCB and measurement result are presented.