Compact Dual T/R Module Controller Board Design using Embedded Resistor Technique

Abstract

In the present work we report design and fabrication of High Speed printed Circuit Board (PCB) with Microvia and Embedded Resistors for the Design and Realization of Compact Dual Transmit/Receive Module Controller (DTRMC) card for active phased array Radar. Embedded passive technology enables classical passive surface mount components such as resistors, capacitors & inductors to be integrated inside the layers of the primary interconnect substrate. The main drivers for the embedded resistor technology are size reduction, increased functionality, improved high frequency performance and also increased reliability due to elimination of solder joints. These advantages led to Design and Development of Compact DTRMC card. The board controls Transmit/Receive Modules (T/R Module), consisting of single Lattice Field Programmable Gate Array (FPGA) which controls 2-Transmit/Receive modules simultaneously. The overall objective of this controller is to receive command and control data from Higher Level Controller, configures both the T/R Module as per commands and also monitors the Status/Health of both the Modules. The Communication link is High speed 10-Mbps full duplex Low Voltage Differential Signalling (LVDS) serial link. Compact DTRMC PCB Layout design is done optimally using controlled impedance techniques. Layout is done to take care of crosstalk, reflections and Electromagnetic Interference (EMI) issues. The Multilayer PCB is designed to ensure Electromagnetic Compatibility (EMC) so as to meet the high-speed performance requirements of control signals required for both the T/R modules. The Compact DTRMC card is an 8- layer PCB with Microvia & 28nos of embedded resistors with a csBGA package of 0.5 mm pitch. Via-on-pad technique is adapted for routing the signals near BGA. The Board is designed, fabricated, tested and found to meet all the requirements.