An ongoing challenge in electrical engineering is the design of antennas whose size is small compared to the broadcast wavelength λ. One difficulty is that the radiation resistance of a small antenna is small compared to that of the typical transmission lines that feed the antenna, so that much of the power in the feed line is reflected off the antenna rather than radiated unless a matching net...

this paper presents an e-ring shaped printed monopole antenna for uwb applications with dual notched bands performance. in order to generate single frequency band notch function, we applied a u-ring shaped monopole antenna, and by inserting a rectangular ring in the centre of it an e-ring shaped radiating patch created and a dual band-notch function can be achieved. the measured bandwidth of th...

In this project we first define the model of a broadcast channel in the network information theory basis. This model was proposed in the pioneering work of Cover [1] for the first time. Then we will pay attention to the fact that in a broadcast network, interference from other users can be counted as side information known to the sender. The causal side information was discussed by Shannon in [...

in this paper, a resonant slotted waveguide array antenna with circular boundary has been designed and simulated for mono-pulse airborne radar applications. the antenna parameters are:11% bandwidth in x-band (8.6-9.6ghz),vswr < 2, 38dbi directivity, sidelobes level of - 20db and 3-db beam-widths of 2.1degree. to design this antenna, it is divided into short sections (sub-arrays) each with a uni...

this paper presents the results of a study on the radiation characteristics of a plasma triangular antenna in the vhf band (30-300mhz) applying the method of moment. deriving the current distribution of the antenna, it shows the relationship between radiation characteristics of the plasma antenna and the plasma parameters. both theoretical and numerical results indicate that if the plasma frequ...

A novel coding strategy is proposed for a broadcast setting with two transmitter (TX) antennas and single-antenna receivers (RX). The consists of using space-time block to send common message (to be decoded by both RXs) across the TX antennas, while each antenna also sends private one RXs. relative weight messages from tuned maximize instantaneous achievable sum-rate channel. Closed-form expres...

In this paper a new cooperative transmission scheme is proposed that enjoys some important advantages over similar protocols First it achieves cooperative diversity without relying on orthogonal subspaces e g di erent spreading codes or frequency bands allowing full rate transmission Second its performance degrades gracefully as the path loss between cooperating partners increases never falling...

In this letter, we consider a cognitive radio network consisting of broadcast satellite service (BSS), high-density fixed-satellite (HDFSS), and high-altitude platforms (HAPs) systems. The spectrum utilization within beam coverage is increased by deploying extra HAPs in the pre-determined hot-spot regions to existing systems which BSS HDFSS share frequency bands. Since multiple nodes simultaneo...

In this paper a particle swarm optimization (PSO) algorithm is presented to design a compact stepped triangle shape antenna in order to obtain the proper UWB bandwidth as defined by FCC. By changing the various cavity dimensions of the antenna, data to develop PSO program in MATLAB is achieved. The results obtained from the PSO algorithm are applied to the antenna design to fine-tune the bandwi...