In this paper a modified Gaussian pulse stimulus is employed to improve the accuracy of tumor detection inside breast phantom for 2D reconstructed image results in cylindrical setup of the microwave imaging system. This pulse shaping puts more energy at higher frequencies in contrast with conventional Gaussian pulse shaping in the impulse radar. Hence a wider bandwidth is available to achieve higher accuracy for precise spatial localization. In the present article a simulated cylindrical setup of the microwave imaging system with a modified stimulated pulse is generated. The main purpose of this paper is employing a new stimulating pulse to detect a tumor from a biological phantom for 2D visualization of time-domain results. In order to achieve the goal, the advantages of generating a novel confocal image-reconstructing algorithm based on back-projection method is employed. The advantage conferred by “ high resolution imaging” is that more energy is used at reflected signal than with conventional confocal imaging, and subsequently a relatively lower spatial resolution in identifying the reflected signal is achieved. Simulated results are presented to validate the effectiveness of the proposed method for precisely calculating the time-dependent location of targets.

In this paper a Frequency Selective Surface (FSS) as a UWB electromagnetic shield is introduced. The proposed FSS comprises a quasi-J. C-Jerusalem Cross-and a copper ring, which are located at both sides of a FR4 substrate and can represent a S. E-Shielding Effectiveness-better than 20dB in 90% bandwidth of Ultra Wide Band frequency. This structure is compact and thin. Each cell comprises J. C elements and a ring at two sides of a FR4 board with 3. 2mm thickness, dielectric constant of 4. 4, and loss tangent of 0. 02. The structure has a 24×36 elements with dimensions of 288×432mm. Also the simulation and measurement results are in good agreement.

Time Reversal (TiR) technique mitigates the complexity of receiver in UWB indoor channels, but is very sensitive to the channel estimation error. The effect of channel imperfection on TiR technique is considered in this paper. At first, the Bit Error Probability (BEP) of the TiR-UWB communication system under the assumptions of the simple Matched Filter (MF) receiver with the channel estimation errors is derived in closed-form. Moreover, based on optimal MMSE estimator receiver, a pre-filter is calculated in closed-form to improve the performance of the TiR-UWB system in an imperfect CSI scenario. Furthermore, a two stage iteration-based algorithm is developed at transmitter to calculate a pre-filter in MF receiver. This improved algorithm causes the channel estimation error tends to zero in some steps for the TiR-UWB system with MF. The initial value for this iteration-based improved algorithm is considered to be closed form pre-filter calculated in TiR-UWB system with optimal MMSE estimator. Finally, exhaustive simulations are done to demonstrate the performance advantage attained by the improved algorithm.

This paper investigates the Multi-band OFDM (MBOFDM) based physical (PHY) layer proposal for IEEE 802.15.3a working group on short-range high data-rate Ultra-wide-Band (UWB) communications. An overview of the MB-OFDM PHY layer architecture with its various parameters is presented and the optimal choice of critical parameters is discussed. Next, we derive the theoretical un-coded Bit Error Rate (BER) of MB-OFDM over the Rayleigh fading channel. Performance results over realistic IEEE UWB channel models are analyzed and compared to a pulsed-OFDM based approach. Although pulsed-OFDM was presented in the literature as an enhancement to the MB-OFDM approach, simulation results showed that with same redundancy-factor, both systems give almost similar BER performance.

A compact triple band notched ultra-wideband (UWB) monopole antenna is presented in this paper. Split Ring Resonator (SRR) structure is exploited in various forms like Complementary Split Ring Resonator (CSRR), Split Ring Resonator Pair (SRRP) and CSRR on Electromagnetic Band Gap (EBG) structure to produce triple band notched characteristics in UWB spectrum. The proposed antenna produces triple band notched functions with integration of all three types of SRR on primary antenna. The parametric analysis of each form of SRR is presented along with their current distribution effects on triple band notched antenna. The proposed antenna prototype is fabricated and measured results are also compared with simulated one to understand the discrepancies. The measured and simulated results are presented to investigate the band notching characteristics of suggested antenna in terms of VSWR and radiation characteristics.

In this paper, a novel CPW-fed antenna is presented for UWB applications. The antenna mainly comprises of a simple circular patch and a modified ground plane. The inclusion of two novel symmetrical rectangular slots with inner area of 3×2.8 mm2 to the top corners of the antenna creates a new path for the current and consequently leads to the bandwidth enhancement. A rectangular stub is also adopted to further broaden the antenna impedance bandwidth. The proposed antenna has a compact size of 20×20×1.6 mm3 and covers the wide frequency band of 3-23.5 GHz (154%). Constant gain and suitable radiation patterns are observed for the presented antenna. Good agreement between the simulated and measured results clearly shows the validity of the proposed structure. The design steps and bandwidth enhancement process are discussed in detail.

The performance of a non-coherent UWB receiver with Binary pulse position modulation is simulated with MATLAB; taking into account the effect of nonlinearity, noise, pulse shape and channel effects. This simulation examines the minimum requirements for LNA, AGC, squarer, and operational transconductance amplifier in analog front-end for sensor network application with 100Kb/s data rate and 10-3 BER. The linearity requirement in OTA is achieved using Gilbert cell OTA with the technique of multiple gated transistors. For sensor network applications, analog front-end modules must have 4dB NF (Noise figure),-12dBm IIP3, 50dB gain and-75dBm sensitivity for 100Kb/s data rates. The transceiver power consumption is assumed to be below 50mW. The performance of energy detection non-coherent receiver is simulated in Simulink of MATLAB, it shows that BER of Gaussian pulse is lower than doublet and 4 th Gaussian pulse. By increasing the number of transmitted pulse per bit and IIP3, the performance of receiver is improved.