In this paper, we present a low-profile, compact, ultrawideband antenna that uses a set of closely coupled radiators. The system of two coupled radiators has two different linearly independent modes of operation with complementary frequency bands of operation. These include the differential mode and the common mode of operation. When the antenna is excited in the common mode of operation, it ac...

Determining acoustical loading conditions on radiators in an underwater array is of great importance to predict the performance of the array. Acoustical interactions between radiators generate a non-uniform distribution of acoustic loading over the radiating surface of the array and often cause performance degradation on the directivity patterns as well as the transmit frequency response of the...

For restricted-power UHF* communication systems, as defined in FCC Rules and Regulations Title 47 Part 15 Subpart C “intentional radiators*”, communication range capability is a topic which generates much interest. Although determined by several factors, communication range is quantified by a surprisingly simple equation developed in 1946 by H.T. Friis of Denmark. This paper begins by introduci...

The CLEO-III Detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

1 LO, T.K : 'Miniature aperture-coupled microstrip antenna of very high permittivity', Electron. Lett., 1997, 33, pp. 9-10 2 PINHAS, s., and SHTRIKMAN, s.: 'Comparison between computed and measured bandwidth of quarter-wave microstrip radiators', IEEE Trans., 1988, AP-36, (ll), pp. 1615-1616 3 WATERHOUSE, R.B : 'Small microstrip patch antenna', Electron. Lett., 1995, 31, pp. 604605 4 LUK. K.M.,...

The Dirc, a novel type of Cherenkov ring imaging device, is the primary hadronic particle identification system for the BABAR detector at the asymmetric B-factory Pep-II at SLAC. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiators and light guides. BABAR began taking data with colliding beams in late spring 1999. This ...

This paper presents a review of the most important features of the Shorted Annular Patch antennas. These radiators have several mechanical and electrical advantages with respect to other microstrip geometries. In particular, the presence of the short in the central zone of the antenna provides increased radiation flexibility which permits to control the antenna beam aperture. In order to demons...

We look at a variant of the Hamilton circuit problem, where the input is restricted to hexagonal grid graphs. A hexagonal grid graph has a vertex set that is a subset of the grid points of a regular hexagonal tiling of the plane and edges corresponding to hexagon sides. We show that Hamilton circuit in hexagonal grid graphs is NP-complete.

One of the advantages of microstrip patches over conventional antennas is their small size. However, there are many present day applications where even these small radiators are too large. Conventional microstrip antennas assume infinitely large ground plane dimensions and thus they are large in size. The size of ground plane is the limitation of antenna characteristics and compactness. In this...

A cost effective implementation of a 'Smart Antenna' is limited due to the number and high cost of RF array elements, RF distribution as well as phasing elements. Shaped Dielectric Lenses perform the task of collimation, to obtain multiple beams in a fixed set of directions. Lenses are inherently broadband, lower in cost, easy to fabricate, have lower dimensional tolerances, and act a...