This study presents new antenna schemes suitable for cognitive radio communications. The antenna structures consist of a ultra wide band (UWB) sensing antenna, and a frequency reconfigurable communicating antenna both incorporated into the same substrate. Two different techniques to achieve the required frequency agility are proposed. The first one is based on a rotational motion of the radiati...

Ultra wideband (UWB) communications is a promising technology which provides high data rates for short-range communications. There are currently two proposals as UWB standards, namely, multiband orthogonal frequency division multiplexing (MB-OFDM) UWB and direct-sequence (DS) UWB. These two standards can cause interference on each other and also to other wireless technologies when they are loca...

Ultra Wideband (UWB) has a number of applications that make it attractive for a variety of applications such as microwave imaging, wireless communications, ground penetrating radars, remote sensing and phased arrays. This paper offered the design of a tapered slot Vivaldi antenna for ultra-wideband application using FR4 substrate which has relative permittivity of 4.4. The Vivaldi Antenna is de...

In this letter, a design of Compact Ultra-Wideband (UWB) bandpass filter with a switchable notch band for WLAN (5.3-5.9GHz) interference rejection is proposed. As 5.3-5.9GHz wireless local area network (WLAN) is existed in UWB spectrum range (3.1 -10.6GHz) and may interfere with UWB system operation. The UWB bandpass filter is implemented using a basic multiple mode resonator (MMR) structure fe...

Band-notch characteristic has been of great interest recently to overcome the electromagnetic interference of Ultra-wideband systems (UWB) with other existing ones. In this paper, we present a novel microstrip-fed antenna with band rejection property appropriate for UWB applications. Band-notch characteristic has been achieved by adding a rectangular resonant element to the ground section. A pr...

In this paper, a novel configuration of circular ultra-wideband (UWB) antenna with band rejection characteristic is presented. In order to obtain this characteristic, the spiral loop resonators resonating at the rejection frequency are located in both sides of the circular radiating patch. This novel structure provides the band-notched characteristic without the degradation of the UWB antenna p...

In this paper we propose frequency and time hopping pulse position modulation (FTH-PPM) ultra wideband (UWB) for multiple access communications. We have derived and investigated the bit error probability for the multi-user synchronous transmitter case in multipath channels with Additive White Gaussian Noise (AWGN). Simulation results show that bit error probability performance of FTH-PPM UWB ou...

This paper presents design, simulation, fabrication and electrical analysis of a triple notched band UWB band pass filter. Short circuit stubs and microstrip line defected structures are used to design a triple notched band UWB filter. The proposed UWB BPF consists of five short circuited stubs of quarter wavelength attached to the feed line. The notched bands are created by introducing three U...

Ultra-wideband (UWB) technologies have been anticipated for use in wireless body area networks (WBAN) because of their low power consumption and anti-multipath capabilities. This chapter presents the UWB (3.1–10.6 GHz) propagation loss in WBAN scenarios between on-body antennas in three different surrounding environments. The measurements were performed in a 3-m radio anechoic chamber, a classr...

In this paper, a coplanar waveguide (CPW) fed slot antenna using fractal-shaped isosceles trapezoidal corrugations is designed and presented for Ultra-Wideband (UWB) applications. The proposed formed by regular hexagonal patch through CPW feed line radiates amidst notched wide slot. edge of the shaped fractal structure that five notches. printed on RO4350B substrate having compact size 0.305λ0 ...