A BITE subsystem for phased array transmit antenna control

In the paper, a BITE subsystem to control radar antenna system parameters with transmit pulse power up to several hundreds KW is described. The proposed BITE subsystem is used to control parameters of the transmit beam forming network with 24 radiating structures. At the input of the transmit beam forming network the input pulse power is measured by a detector placed in the decoupled port of the directional coupler. At all outputs of the beam forming network, directional couplers with the same type of detectors are used to control the output power distribution. Output voltage from detectors are supplied to 8-bit microcontrollers with built-in A/C converter and information about amplitude distribution at the input of antenna rows and input VSWR of the antenna rows after final processing in the master microcontroller is supplied to the radar central computer. As a test signal the pulse power from the radar transmitter is used. Antenna parameters are controlled at nominal power level in on line mode of radar operation. Special attention is paid to the reduction of the cost of the BITE subsystem, low cost components are used and a new design of the low cost directional coupler is proposed.