TEM antenna's arrays and high power radiators of UWB electromagnetic sub-nanosecond impulses

Abstract

Progress in researches of our laboratory is presented concerning creation, operation and diagnostics of the high power radiators for quasi-mono-polar short electromagnetic impulses (SEMI) in range of centimetric and decimetric waves. Autonomous radiating module contains: the ultra-wideband (UWB) antenna of a TEM-horn type, the excitation pulse high voltage semiconductor generator (GpV), power source and control unit. Known basic TEM-horns with square cross-section are best UWB antennas but with non-high aperture efficiency of Aeff/Aa ∼ 0.5 (Aeff — effective aperture in receiver/transmitter modes, Aa — face area of the TEM-horn). We obtained increase of this efficiency up to 1.0 by constructing UWB antenna as array with four TEM-horns with shielded plates in them for return currents. Each TEM-horn was connected to its two-wire line and then to the matched HV-HF 50 Ohm coaxial antenna feeder. The antenna array apertures had side sizes 16–60 cm. Used GpV generators were produced by “FID Technology” company with parameters: mono-polar impulses 10–100 kV, rise-time 0.04–0.15ns and half-width 0.3–1.5ns. The modules radiated the SEMI waves with UWB spectrums 0.1 GHz-10GHz (one module radiated spectrum with fh/fl ∼ 30), and with the radiation effective potentials of Ep(R) ∗ R = 20–400 kV (product of peak E-field in far-zone by the R-distance). Parameters of the SEMI waves were measured by calibrated sensor with characteristics: sensitivity 0.32 V/(kV/m), rise-time 0.03ns, duration up to 7ns. The radiators for the SEMI waves with ∼10kV/m amplitudes and 0.5–100 kHz-pulse repetition rate were successfully used to examine various electronic devices on electromagnetic immunity.