Thin stable atmospheric layers cause VHF radars to receive increased echo power from near zenith. Layers can be tilted from horizontal, for instance by gravity waves, and the direction of VHF “glinting” is measurable by spatial domain interferometry or many-beam Doppler beam swinging (DBS). This paper uses the Middle and Upper atmosphere (MU) radar, Shigaraki, Japan as a volume-imaging radar wi...

In this paper we present an ultra low-voltage (ULV) floating-gate (FG) transconductance amplifier The amplifier can operate at supply voltages below 1V in a standard digital double poly CMOS process . The amplifier consists of a sinh shaped output current transconductance amplifier and a tanh shaped transconductance amplifier.

[1] We have developed a new method for extracting ionospheric parameters from broadband RF data collected in low‐Earth orbit using coherent matched filters. The coherent matched filter uses the full time series of the electric field and matches the Fourier transform of these data with an ionospheric transfer function. This approach was applied to both lightning and human‐made data transmitted o...

The current global move to switch from analogue to digital terrestrial television has opened up an opportunity for the re-allocation of valuable spectrum resources in VHF/UHF frequencies. In one way, spectrum bands once used for analogue TV broadcasting will be completely cleared, leaving a space for deploying new licensed wireless services, and in another way, digital terrestrial television te...

This paper reports on implementation and high-Q operation of thick bulk mode VHF capacitive disk resonators with reduced motional resistance. Single crystal silicon (SCS) disk resonators as thick as 18 m with capacitive gap size of 160nm (aspect ratio>110) are fabricated on SOI substrates using a three-mask version of the HARPSS on SOI process. The new resonator design with increased number of ...

rr HE AEROVOX RESEARCH WORKER for July, 1949 contained a discussion of the fundamental properties of the half -wave dipole antenna and defined three basic configurations in which multiple dipoles are used to obtain desirable directional effects in transmitting or receiving radio signals. These arrangements included; collinear dipoles, broadside dipoles, and end -fire dipoles of both the driven ...

This article outlines a research program for an anthropology of viral hemorrhagic fevers (collectively known as VHFs). It begins by reviewing the social science literature on Ebola, Marburg, and Lassa fevers and charting areas for future ethnographic attention. We theoretically elaborate the hotspot as a way of integrating analysis of the two routes of VHF infection: from animal reservoirs to h...

In this paper, together with its Part II, the impact of relaying and adaptive modulation and coding (AMC) on data throughput in narrowband wireless multi-hop networks is investigated. This part focuses on the physical layer of a single-carrier narrowband time division multiple access (TDMA) transmission in the very high frequency (VHF) band. The transmission chain is designed for a narrowband, ...

This work deals with the design of multimode/multifrequency airborne radar suitable for imaging and subsurface sounding. The system operates at relatively low frequencies in the band ranging from VHF to UHF. It is able to work in two different modalities: (i) nadir-looking sounder in the VHF band (163MHz) and (ii) side-looking imager (SAR) in the UHF band with two channels at 450MHz and 860MHz....