Directional antennas provide angle-ofarrival information, which can be used for localization and routing algorithms in wireless sensor networks. We briefly describe three classical, major types of antennas: 1) the Adcock-pair antenna, 2) the pseudoDoppler antenna, and 3) the electronically switched parasitic element antenna. We have found the last type to be the most suitable for wireless senso...

A new type of directional dual-band antenna is developed for 2.4/5 GHz wireless applications. The dual-band antenna consists of a longer dipole for the lower band and a pair of shorter dipoles for the upper band. A simple coupling microstrip line is employed to excite the dipoles. Both the dual-band antenna and the feeding microstrip line are printed on the same substrate, leading to a fully pl...

Wireless ad hoc networks have traditionally been assumed to use omni-directional antennas. However, it has been recently recognized that the use of advanced antenna technologies could help alleviate the capacity limitations of multi-hop wireless networks, stemming from interference generated in the shared medium [1]. Adaptive array antennas have the ability to automatically respond to an unknow...

We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk separated from a planar gold layer by a few tens of nanometers thick dielectric layer. The emitters are shown to radiate through the entire patch antenna in a highly...

Coupling nanoscale emitters via optical antennas enables comprehensive control of photon emission in terms of intensity, directivity and polarization. In this work we report highly directional emission of circularly polarized photons from quantum dots coupled to a spiral optical antenna. The structural chirality of the spiral antenna imprints spin state to the emitted photons. Experimental resu...

The proposed wideband shorted planar inverted cone antenna (SPICA) has been described as a two element antenna array in this paper. The two element array by this antenna with proper phase of excitation and spacing between the elements provide superdirective array characteristic. This array gives peak endfire directivity from 3.502 dBi to 10.3 dBi and radiation efficiency above 98% in the operat...

This work describes the adaptive antenna array concept with seven patch elements in a hexagonal arrangement. With this structure it is possible to configure the radiation pattern to obtain directional patterns with high directivity and gain. The software IE3D, from ZELAND, was used to optimize and analyze the antenna array for applications at 1.9GHz. The return loss results and radiation patter...

In this paper, the effects of antenna pattern and antenna polarization on indoor obstructed (OBS) wireless channels are investigated experimentally. Our results show that linearly polarized (LP) directional antennas are more effective in combating multipath components than other types of antennas in OBS channels, The measurement results are verified with a deterministic wide-band propagation mo...

Smart antenna (or directional antenna) technology has been developed recently, which can control its antenna beam pattern to a specified direction by software. Medium access control (MAC) protocols using smart antennas, called directional MAC protocols, have the following potentials: higher spatial reuse, larger extension of communication range, less interference and higher total throughput com...