J. M. Zamanillo

X-band Gunn diode oscillator for a multiple-frequency continuous-wave radar for educational purposes

A low-cost, high-performance X-band Gunn diode oscillator for educational and research purposes has been developed. The cavities have been manufactured on a standard WR90 rectangular waveguide with UBR100 flange in order to make it compatible with the waveguide circuitry usually available in a basic microwave laboratory. The capability of sweeping the whole X band at constant output power and low phase noise, as well as the low cost of its components, make this device suitable for users at any level. As an example of its many educational applications, a multiple frequency continuous-wave (MFCW) radar has been developed, and the results of the laboratory implementation are shown.

Large-signal model for microwave FETs under CW laser stimulation: Research Articles

In this article, a linearity-improving technique for active antennas and arrays, based on spatial power combining, is presented. An auxiliary branch is employed to cancel the radiation pattern at the intermodulation distortion (IMD) components, either in the main-beam direction for a subarray or in all elevation angles for a single antenna element. The need for precise amplitude and phase control over the IMD currents in the array auxiliary elements is demonstrated, quantifying the possible degradation suffered in the carrier-to-intermodulation distortion (CIMD) ratio improvement obtained when this solution is applied. The potentialities of implementing the derivative-superposition technique in small- and large-signal regimes, both in an array and in an antenna element, are finally proposed.