A simple low-cost coplanar twin-slot active antenna oscillator for wireless applications

This paper presents a compact, simple, low-cost coplanar waveguide active antenna oscillator which can be used for wireless communication applications. The circuit uses the active MGA86576 MMIC amplifier, which is biased through its output port using simple lumped elements. A closed feedback loop is implemented with two slot antennas fed by coplanar waveguide transmission lines. The paper presents a design procedure to systematically dimension the different parts of the structure until the oscillation condition is satisfied. An active antenna oscillator has been designed, manufactured, and tested, and measured results are in good agreement with predictions. The circuit exhibits a very clean, stable oscillation, and the radiation patterns are smooth and quasiomnidirectional. The measured gain of the active antenna is 3.2 dBi. © 1999 John Wiley & Sons, Inc.