This paper presents a very low profile circular UHF small antenna with a radiating body transformed from a monopole. The proposed radiating body is gradually improved by analyzing fundamental modes of the structure with different ground planes via characteristic mode analysis (CMA). CMAs demonstrate operating principles of the radiating body so that a magnetic feeding loop is proposed to excite...

In this article the effects of different engineering parameters of rf-driven ion sources with an external spiral antenna and a quartz rf window are studied. This article consists of three main topics: the effect of source geometry on the operation gas pressure, the effect of source materials and magnetic confinement on extracted current density and ion species, and the effect of different anten...

We identify critical problems in Plasma Heating and Current Drive plasma-wave interaction physics and antennae concepts/technology for large fusion devices, including tokamaks, stellarators, mirror traps and constructing ITER for all major methods like ECRF, ICRF, NBI and LHH. Analysis is based on experiments in large machines and modelling with 3D ICRF and ECRF recently developed full wave PST...

Tests in July, 1998, of an improved version of the prototype VETEM system demonstrated improved depth of investigation at the Cold Test Pit (CTP) at the Idaho National Environmental and Engineering Laboratory (INEEL). The improved depth of investigation is due primarily to the development of larger loop antennas and a new transmitter capable of driving up to 30 times more current than the origi...

A comprehensive analysis of electromagnetic (EM) inversion applied to pavement profiling by using a monostatic ground penetrating radar (GPR) is presented. Since in GPR systems using transfers EM (TEM) horns, the antenna is positioned close to the the investigated medium and a strong EM interaction occurs. This effect is taken into account by modeling the antenna with equivalent sources placed ...

Mobile network operators demand small base station antennas and high physical layer throughputs. In the downlink, high physical layer throughputs can be achieved by exploiting transmit diversity. Given that the correlation between different propagation paths reduces the achievable throughput, it is commonly conjectured that the greater the transmit antenna spacing, the better the radio link per...