Cognitive radio (CR) is a very promising technology of future wireless communications that has greater demands for antenna designs. One practical antenna is a reconfigurable antenna that has dual mode operations, i.e. scanning a free RF spectrum and transmitting or receiving information data via a CR link. One possible compact antenna configuration is based on the dipole or monopole that has na...

In the paper, wideband antenna arrays aimed at microwave imaging applications and SAR applications operating at Ka band were designed. The antenna array feeding network is realized by a low-loss SIW technology. Moreover, we have replaced the large feed network comprised of various T and Y junctions by a simple broadband network of compact size to more reduce losses in the substrate integrated w...

Abstract—In this paper, an ultra high frequency (UHF) low-profile antenna is proposed; it is based on the discone antenna but with addition of a back cavity, a short-circuiting structure and a two-plate top structure in order to achieve both low-profile and wideband. It is simulated and prototyped. The test results show that the antenna has an omni-directional radiation pattern in the horizonta...

A small wideband microstrip patch antenna is introduced. The antenna is designed to function in the 5-6 GHz wireless LAN bands. It achieves multi-band functionality through the addition of a slot to a square patch (21 mm by 21 mm by 2.6 mm). The proposed antenna also generates circular polarization and has a 3 dB axial ratio bandwidth of 2.8%. The impedance bandwidth of the antenna is more than...

This paper presents a design of RFID reader antenna, which is equipped on a chipattaching machine producing the RFID tags. Such an antenna is constrained to read exclusively one tag only for the purpose of functional check of the whole tag when it passes the reader antenna, namely, the other neighbour tags on the same rolling band are ignored that time. A wideband microstrip antenna is designed...

Wideband, wide-scan antenna arrays are a promising candidate for the future wireless networks and as well as an essential part of experimental radio astrophysics. Understanding the underline physics of the element performance in the array environment is paramount to develop and improve the performance of array systems. The focus of this thesis is to develop novel wideband antenna array technolo...

In this paper, frequency-tunable microstrip antennas, for cognitive radio applications, are proposed. The approach is based on electrically tuning the antenna’s operating frequency by integrating reconfigurable band pass filters into wideband antenna structures. The design of an open loop resonator (OLR)-based bandstop filter, and its transformation to a bandpass filter, are investigated first....

Two new antenna array designs with advanced beam steering capabilities are described. The first is based on an integrated design using Ferroelectric and Continuous Transverse Stub (CTS) technologies, while the other is based on a hybrid smart antenna approach that combines the desired features from both the adaptive and switched beam approaches. The complementary features of these two analog an...

A dual resonant antenna configuration is developed for multistandard multifunction mobile handsets and portable computers. Only two wideband resonant antennas can cover most of the LTE spectrums in portable communication equipment. The bandwidth that can be covered by each antenna exceeds 70% without using any matching or tuning circuits, with efficiencies that reach 80%. Thus, a dual configura...