Patent ID: 7821447
Filing Date: 2010-10-26
Classification: G01S

Abstract:
1. For use in a radar apparatus comprising a transmitting/receiving antenna, a radio frequency unit connected to said transmitting/receiving antenna and containing at least one monolithic microwave integrated circuit and a bias circuit for said monolithic microwave integrated circuit and a processing unit, connected to said radio frequency unit, for processing transmission and reception of radio waves, a method for adjusting an analog bias value to be applied to said bias circuit, comprising the steps of: providing in said bias circuit a D/A converter to be connected to a gate terminal of said monolithic microwave integrated circuit; connecting a radio wave signal generator to an antenna connecting end of said radio frequency unit so as to cause a received signal to be output from said radio frequency unit; in this condition, connecting a test processing unit in place of said processing unit; connecting to said test processing unit a control apparatus to which said received signal is to be input; and causing said control apparatus to execute the steps of: outputting an initial value of a digital bias value to said D/A converter through said test processing unit; subsequently measuring a radio frequency characteristic of the received signal output from said radio frequency unit in response to said initial value, calculating a target value for said digital bias value based on said measured radio frequency characteristic, and supplying said target value to said D/A converter through said test processing unit; measuring the radio frequency characteristic of the received signal output from said radio frequency unit in response to said target value and determining whether said measured radio frequency characteristic lies within specified limits; if said measured radio frequency characteristic lies within said specified limits, then determining said target value as a bias adjusting value to be applied to said monolithic microwave integrated circuit; and if said measured radio frequency characteristic lies outside said specified limits, then recalculating said target value until said measured radio frequency characteristic comes within said specified limits.