Phase and Gain Matched Low Noise Amplifier for Phased Array Radar System
Problem
An established defense contractor had run into a critical obsolescence situation. Their previous suppliers of a key, high performance low noise amplifier used in a strategic phased array radar system were no longer able to manufacture the item. In production for some 25 years, the discrete GaAs FET devices were obsolete and no longer available, and the supplier did not have the engineering capability for a new design. Without the amplifier, new systems could no longer be fielded, and existing systems had no spares. Besides stringent requirements for low noise and VSWR, an added complexity was that all amplifiers had to match each other in gain, phase and electrical length over a wide temperature range. This meant that new amplifiers produced today with modern FETs and passive devices, such as ferrite isolators and switches, had to match units already in the field.
Solution
System engineers at the defense giant turned to CAP Wireless for help. Working closely with the customer, CAP engineers were able to devise a new design that met the challenging technical specifications and form factor with a large margin. The new LNA incorporated surface mount components and modern FET technology built on a multilayer RF printed circuit board, along with an integrated high performance ferrite isolator. Produced using modern automated surface mount equipment with minimal touch labor, the unit replaces a product that required hand-soldering of transistors and chips on multiple circuit boards. The result is a robust, repeatable, form, fit and function replacement for a critical defense system that will be in production for several years.
These LNAs have operated reliably in service for over 10 years in adverse environments. CAP enjoys being a valued contributor to the contractor and the program.
