Tunable Electrically Small Conical Folded Dipole Antenna Used as a Mesoband High-Power Microwave Source
High-power microwave (HPM) moderate-band (MB) sources combine simple design concepts seen in ultrawideband (UWB) sources, but with longer pulses to produces higher energy spectral densities. These factors allow the designs to be more compact and less complicated than many narrowband HPM sources. In this letter, we will demonstrate from both simulation and experimental results the operation of a electrically small, tunable, self-resonant, mesoband source utilizing a conical folded dipole antenna as the energy storage and radiating element. The system is based on a previous design for an HPM folded helix antenna that has a resonant frequency of 46 MHz and is charged to 70 kV. The design presented here utilizes a tunable capacitance that allows the resonant frequency to be tuned between 52 and 87 MHz with ka =0.58 at the lowest resonant frequency.
Compact antenna concepts for mesoband HPM applications
High power microwave (HPM) systems often suffer from being large in volume and mass. Specifically the antennas for HPM systems tend to be very large, as the field levels must be kept below what is required for holdoff in air. The general utility of HPM systems could is enhanced when they are made low profile, increasing the number of platforms and applications for which they can be considered. In this paper we present our modeling and experimental work on electrically small antennas for HPM (or more appropriately HPEM, since we are working below the microwave band). We consider two concepts: a modified biconical helix antenna for use at frequencies below 50 MHz and an adapted magnetic EZ antenna for use in the UHF (500 MHz). In both cases, demonstrated performance at small sizes between ka = 0.4 and 0.5 is realized.
A slowly rotating coil system for AC field measurements of Fermilab Booster correctors
A method for measurement of rapidly changing magnetic fields has been developed and applied to the testing of new room temperature corrector packages designed for the Fermilab Booster Synchrotron. The method is based on fast digitization of a slowly rotating tangential coil probe, with analysis combining the measured coil voltages across a set of successive magnet current cycles. This paper presents results on the field quality measured for the normal and skew dipole, quadrupole, and sextupole elements in several of these corrector packages.