Compact semicircular directive dipole antenna for UWB applications

Abstract

A high-efficiency and high-gain slotline fed directive dipole antenna for UWB communication and imaging application has been developed. The antenna offers a 2:1 VSWR bandwidth of greater than 10 GHz starting from 3.1 GHz. This antenna offers an average gain of 8 dBi in the entire operating band. The simulation and experimental results show that the proposed antenna exhibits high gain and stable directive radiation patterns which are suitable for imaging applications Introduction: One of the main uses of ultra-wideband (UWB) technology other than high data rate communication is in the field of imaging. But it is very difficult to meet the important criteria such as high gain, directive radiation patterns in the entire band, uniform flat group delays of less than 1 ns and compactness, which are necessary for an imaging antenna. A number of UWB antennas that exhibit moderate gain have been presented in the past decades. The microstrip-fed tapered slot antenna presented in [1] offers an average gain of less than 6 dBi and does not possess stable radiation patterns in the entire frequency band. The antipodal tapered slot UWB antenna presented in [2] obtains its wide bandwidth by merging more than six resonances and does not offer directive radiation patterns in lower bands. In [3] the authors presented a tapered slot UWB antenna, which has a complex structure and non-directive radiation patterns. Hoods and Karacolak in [4] presented a Vivaldi antenna, which offers a small gain and the patterns are nonuniform. In [5] the authors presented an exponentially tapered slot UWB antenna, which offers moderate gain with a large size. The dipole antenna presented in [6] offers a gain of less than 5 dBi and posseses non-uniform radiation patterns at different frequencies. In [7] the authors discussed different UWBs, which are suitable for medical applications. However, these antennas occupy a relatively large space.In this Letter, we present a simple compact uniplanar semicircular directive dipole antenna suitable for UWB imaging applications. This antenna offers a bandwidth greater than 10 GHz starting from 3.1 GHz and an average gain of 8 dBi in the entire frequency band. It possesses directive radiation patterns in all frequencies with a crosspolar level better than 215 dB and a front-to-back ratio greater than 15 dB, which is very suitable for imaging applications. The simulation and experimental studies show that the antenna offers good reflection characteristics, high gain and a robust directive radiation pattern in the entire frequency band.

Application of illuminating modes concept in modal expansion of elliptical resonator

“…Once the basis functions in the form of the current modes have been defined, we can apply them to Galerkin procedure for solving equation (1). As a result we obtain the expansion coefficients of current modes a e mn , a o mn (see equations (4)).…”

“…Many types of numerical techniques included in full-wave simulators are utilised in order to design planar ultra-wide band (UWB) antennas [1,2]. The greater part of them is expected to examine an arbitrary shape of an antenna.…”

Ultra‐wideband directive antenna based on an inclined cone body

“…On the other hand, different kinds of structures which perform with omnidirectional radiation pattern have been modified to be employed in directive radiation applications. Many of them are based on the well known monopole or dipole and some directors or reflectors are employed in order to obtain the directivity in the radiation pattern [11][12][13].…”

A CPW-Fed Wide Slot Ultra-Wideband Antenna with Triple Band Rejection Characteristics

“…Their radiation patterns should be omnidirectional and they should be able to operate at multi-band and multi-mode. Therefore, many printed UWB antennas have been proposed and investigated using various structures, including monopole antenna and dipole antennas [2]- [5]. Among them, CPW-fed wide slot antennas are attractive for easy integration into circuits [3].…”