This paper describes the design of a balanced signal distribution system to feed an n by n set of mixers with local oscillator signals equal in frequency, phase and magnitude. This system is used in a planar n by n receiving/ transmitting array that measures and/or controls the direction of arrival of the received/transmitted signals. The design steps are clearly described. Optimization goals and variables are specified and the results of linear, electromagnetic and combined simulations are given and compared. The final product layout is shown and its performance is described. This paper is a typical example of a successful computer-aided design which saves time, effort and money before manufacturing a prototype. It introduces the active power divider as a zero-loss signal distribution device.

In this paper we propose a new measure of amplifier nonlinearity; namely, the small signal gain degradation due to large signal capture of the amplifier power. This new criterion for linearity evaluation is specially important in repeaters where received signals are not a priory known. A 5 th order mathematical model is used to characterize this phenomenon. After a thorough comparison between different linearization techniques, we select the classical feed-forward linearization. We adapt the FF linearization circuit to the total input signal power at different conditions and simulate the small signal gain against a large input signal gain in each case. An interesting result was that the feed-forward linearization circuit adapted to the total input power, completely compensates the small signal gain degradation. Although the results are frequency dependent, we can find some average settings to correct the system performance within a certain frequency band. We propose the use of a general power detector and a set of look-up tables for system adaptation.