Introduction Travelling wave (TW) MRI is a relatively new imaging technique. An antenna is used to generate a TW which then propagates through the bore. This excites all the spins in the subject, allowing large volumes to be imaged simultaneously and reducing B1 field inhomogeneities. So far, most TW studies have used a patch antenna to create the TW, as they are simple in design and can be con...

The indirect two-port reflection method for measuring antenna impedances is reviewed using scattering parameter techniques and developed into a more accurate low perturbation optically coupled transmission measurement. This transmission measurement infers the antenna impedance by measuring the voltage induced in a number of loads connected to the antenna port with reference to the antenna used ...

In this paper, a novel CPW-fed antenna is presented for UWB applications. The antenna mainly comprises of a simple circular patch and a modified ground plane. The inclusion of two novel symmetrical rectangular slots with inner area of 3×2.8 mm2 to the top corners of the antenna creates a new path for the current and consequently leads to the bandwidth enhancement. A rectangular stub is also ado...

In this study, a radiation pattern reconfigurable microstrip antenna is designed and fabricated. The antenna’s radiation pattern is directed in 9 different angles by employing a radiating patch and embedding complementary split ring resonators (CSRR) on the ground plane. The radiating patch is of circular shape, while for CSRR elements both circular and rectangular shapes are investigated. The ...

The effects of parasitic elements on the voltage standing wave ratios (VSWR’s) of two antennas are investigated. First, a parasitic monopole is used for a normal-mode helical antenna. The VSWR investigation shows that dual-frequency operation is obtained by the parasitic element effects. The dualfrequency operation is revealed as a function of monopole position above a ground plane (monopole he...

Due to the rapid development and widespread usage of various communication systems, multiband internal antennas are necessary for recent mobile handsets [1]-[3]. To meet the antenna requirement for hand-held terminal, the size reduction is one of the key requirements while maintaining the good multiband and wideband performance. Furthermore, a small intenna that can be integrated into the hands...

In this paper, the design and implementation of plasma antenna array with beam forming is discussed. The structure consists of a circular array of plasma tube enclosed in a unipolar UHF band monopole antenna. Beam forming is possible by stimulated plasma tubes. The combination of the above antenna with plasma excitation controller makes a beam forming smart antenna. An experimental model in UHF...