Various types of medical applications of antennas have widely been investigated. In particular, hyperthermia is one of thermal therapies and is a modality for cancer treatment utilizing the difference of thermal sensitivity between tumor and normal tissue. The author et. al. have developed a coaxial-slot antenna, which is one of thin microwave antennas to be employed for interstitial as well as...

This paper is a review of amateur-built high-directivity wire antennas, for wireless local area network (WLAN), operating at 2.4-GHz frequency range. Those antennas can be deployed for range extension and interference reduction, for example. Covered in this review are a biquad antenna with reflector, Yagi-Uda antenna, and helical antenna. The distinctive feature of these antennas is their ease ...

Abstract—A key feature of upcoming 4G wireless communication systems is multiple-input-multiple-output (MIMO) technology. To make the best use of MIMO, the antenna correlation between adjacent antennas should be low (< 0.5). In this context, we propose a correlation reduction technique suitable for closely spaced antennas (distance, d < λ/40). This technique reduces mutual coupling between ante...

Three dual band planar monopole antennas for wireless local area network (WLAN) application are proposed. The antennas have common configuration in the form of rectangular, rhombic and annular double rings. All the antennas use the self similarity property to exhibit dual band characteristics. The proposed antennas cover the frequency bands of the IEEE 802.11 a/b/g (2.4–2.48 GHz, 5.15– 5.35GHz ...

Optical antennas are of fundamental importance for the strongly localizing field beyond the diffraction limit. We report that planar optical antennas made of split-ring architecture are numerically found in three-dimensional simulations to outperform dipole antennas for the enhancement of localized field intensity inside their gap regions. The computational results (finite-difference time-domai...

This paper presents a simple two-branch transmit diversity scheme. Using two transmit antennas and one receive antenna the scheme provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmit antenna, and two receive antennas. It is also shown that the scheme may easily be generalized to two transmit antennas and M receive antennas to provide a diversity order o...

We study the radiation properties of electrically small resonant antennas (ka < 1) composed of electric-field-coupled (ELC) and complementary electric-field-coupled (CELC) resonators and a monopole antenna. We use such parasitic ELC and CELC “metaresonators” to design various electrically small antennas. In particular, monopole-excited and bent-monopole-excited CELC resonator antennas are propo...

The tunable characteristics of RF MEMS (Microelectromechanical Systems) components enable their integration with antennas providing numerous advantages such as reconfigurability in polarization, frequency, and radiation pattern [1]. Furthermore, the monolithic fabrication of these components with antennas can reduce parasitic effects, losses and costs. This paper presents two tunable frequency ...

It is known that the Alamouti code is the only complex orthogonal design (COD) which achieves capacity and that too for the case of two transmit and one receive antenna only. Damen et al., gave a design for 2 transmit antennas, which achieves capacity for any number of receive antennas, calling it an information lossless STBC. In this paper, we construct capacity achieving designs using cyclic ...

Multiple-input multiple-output (MIMO) technique is one of the most promising solutions for increasing reliability and spectral efficiency of the radio connection in future mobile communication systems. The performance potential of MIMO systems is well established from theoretical point of view. However, much effort is still needed in the experimental verification of those systems using realisti...