scholarly journals Efficient Time-Domain Ray-Tracing Technique for the Analysis of Ultra-Wideband Indoor Environments including Lossy Materials and Multiple Effects

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
F. Saez de Adana ◽  
O. Gutiérrez ◽  
M. A. Navarro ◽  
A. S. Mohan
Keyword(s):  
Ray Tracing ◽  
Mobile Communications ◽  
Time Domain ◽  
Ultra Wideband ◽  
Indoor Environments ◽  
Acceleration Technique ◽  
Uniform Theory Of Diffraction ◽  
The Time Domain ◽  
The University ◽  
Lossy Materials

This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD) for the analysis of Ultra-Wideband (UWB) mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.

scholarly journals Design of Two Novel Dual Band-Notched UWB Antennas

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Bing Li ◽  
Jing-song Hong
Keyword(s):  
Time Domain ◽  
Simple Structure ◽  
The Other ◽  
Ultra Wideband ◽  
Dual Band ◽  
Uwb Antennas ◽  
Monopole Antennas ◽  
Printed Monopole ◽  
The Difference ◽  
The Time Domain

Two novel dual band-notched ultra-wideband (UWB) printed monopole antennas with simple structure and small size are presented. The size of both antennas is25×25×0.8 mm3. The bandwidth of one of the proposed antenna can be from 2.7 GHz to 36.8 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 5.14–5.94 GHz for WLAN applications. The bandwidth of the other is ranging for 2.7 to 41.1 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 4.8–5.9 GHz for WLAN applications. Bandwidths of the antennas are about 512% and 455% wider than those of conventional band-notched UWB antennas, respectively. In addition, the time-domain characteristics of the two antennas are investigated to show the difference between both antennas.

scholarly journals Time-Domain Investigation of Switchable Filter Wide-Band Antenna for Microwave Breast Imaging

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4302 ◽  
Author(s):  
Amir Haider ◽  
MuhibUr Rahman ◽  
Mahdi Naghshvarianjahromi ◽  
Hyung Seok Kim
Keyword(s):  
Time Domain ◽  
Breast Imaging ◽  
Wide Band ◽  
Tumor Detection ◽  
Ultra Wideband ◽  
Good Time ◽  
Area Network ◽  
Microwave Breast Imaging ◽  
The Time Domain ◽  
Domain Performance

This paper investigates the time-domain performance of a switchable filter impulse radio ultra-wideband (IR-UWB) antenna for microwave breast imaging applications. A miniaturized CPW-fed integrated filter antenna with switchable performance in the range of the Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN) bands could operate well within a 3.0 to 11 GHz frequency range. The time-domain performance of the filter antenna was investigated in comparison to that of the designed reference wideband antenna. By comparing both antennas’ time-domain characteristics, it was seen that the switchable filter antenna had good time-domain resolution along with the frequency-domain operation. Additionally, the time-domain investigation revealed that the switchable filter wide-band antenna performed similarly to the reference wide band antenna. This antenna was also utilized for a tumor detection application, and it was seen that the switchable filter wide-band antenna could detect a miniaturized irregularly shaped tumor easily, which is quite promising. Such an antenna with a good time-domain resolution and tumor detection capability will be a good candidate and will find potential applications in microwave breast imaging.

scholarly journals Ultra Wideband Coplanar Waveguide Antenna with an Improved Gain using a Frequency Selective Surfaces (FSS)

2019 ◽  
Vol 8 (9S) ◽  
pp. 145-149
Keyword(s):  
Time Domain ◽  
Coplanar Waveguide ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Frequency Range ◽  
Rectangular Slot ◽  
Improved Performance ◽  
Set Up ◽  
The Time Domain ◽  
Uwb Applications

In this article, an ultra-wideband FSS reflector has been proposed to enhance the gain of a CPW antenna for UWB applications. A CPW fed antenna having dimensions of 38mm×38mm×1.605mm and FSS unit cell having dimensions 14mm × 14mm × 1.605 mm are presented in the paper. A rectangular slot and stubs are interleaved at the outer edges of the patch for achieving desired characteristics of an ultra-wideband for the frequency range of 3.39 GHz to 12.9 GHz. Simulation results carried out using the CST microwave 2016 version in the time domain are presented for the proposed antenna. An FSS unit cell designed and simulated using periodic boundary conditions and floquet ports is presented. The combined setup of an array of FSS reflector behind the antenna has been simulated in the time domain. This set up shows an improved performance in terms of antenna’s gain. A maximum and minimum gain of 8.14 dB and 4.98 dB has been observed with the presence of FSS reflector behind the coplanar waveguide antenna. A significant improvement of 2.9 dB has been observed over the entire band of antenna’s operation

scholarly journals Time Domain Performance of Reconfigurable Filter Antenna for IR-UWB, WLAN, and WiMAX Applications

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1007
Author(s):  
Zhuohang Zhang ◽  
Zhongming Pan
Keyword(s):  
Time Domain ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Low Cost ◽  
Time Domain Analysis ◽  
Local Area ◽  
Ultra Wideband ◽  
Area Network ◽  
Compact Size ◽  
The Time Domain

A novel reconfigurable filter antenna with three ports for three dependent switchable states for impulse radio-ultrawideband (IR-UWB)/wireless local area network (WLAN)/worldwide interoperability for microwave access (WiMAX) applications is presented in this paper. Three positive-intrinsic-negative diodes, controlled by direct current, are employed to realize frequency reconfiguration of one ultra-wideband state and two narrowband states (2.4 GHz and 3.5 GHz). The time domain characteristic of the proposed antenna in the ultra-wideband state is studied, because of the features of the IR-UWB system. The time domain analysis shows that the reconfigurable filtering antenna in the wideband state performs similarly to the original UWB antenna. The compact size, low cost, and expanded reconfigurable filtering features make it suitable for IR-UWB systems that are integrated with WLAN/WiMAX communications.

Time Domain Replica Signal Based Interference Compensation for SP-MIMO/OFDM with Large Delay Spread Channel

2014 ◽  
Vol 5 (4) ◽  
pp. 1-17
Author(s):  
Taichi Sakaue ◽  
Chang-Jun Ahn ◽  
Tatsuya Omori ◽  
Ken-Ya Hashimoto
Keyword(s):  
Mobile Communications ◽  
Time Domain ◽  
Delay Spread ◽  
Impulse Responses ◽  
Channel State ◽  
Large Delay ◽  
Guard Interval ◽  
Interference Compensation ◽  
Mimo Ofdm ◽  
The Time Domain

In mobile communications, MIMO-OFDM transmission performance suffers severe degradation caused by the large delay spread channel greater than guard interval (GI). This is because the excess delay results in considerable inter-symbol interference (ISI) between adjacent symbols and inter-carrier-interference (ICI) among subcarrier in the same symbol. In case of scattered pilot (SP), the interference of pilot signals causes the deterioration of channel estimation. To mitigate this problem, in this paper, we propose the interference compensation scheme using the time domain replica signals. We make the time domain replica signals from detected signals and the excess channel impulse responses over GI. After compensation of the time domain replica signals and the received signals, we recalculate the channel state information (CSI) and the CSI is updated. Finally, we carry out the channel compensation with updated CSI for obtaining accurate compensated signals.

scholarly journals A hybrid method combining the Time-Domain Method of Moments, the Time-Domain Uniform Theory of Diffraction and the FDTD

2007 ◽  
Vol 5 ◽  
pp. 107-113
Author(s):  
A. Becker ◽  
V. Hansen
Keyword(s):  
Method Of Moments ◽  
Hybrid Method ◽  
Time Domain ◽  
Time Domain Method ◽  
Thin Wire ◽  
Uniform Theory Of Diffraction ◽  
Domain Method ◽  
Inhomogeneous Bodies ◽  
Wire Antennas ◽  
The Time Domain

Abstract. In this paper a hybrid method combining the Time-Domain Method of Moments (TD-MoM), the Time-Domain Uniform Theory of Diffraction (TD-UTD) and the Finite-Difference Time-Domain Method (FDTD) is presented. When applying this new hybrid method, thin-wire antennas are modeled with the TD-MoM, inhomogeneous bodies are modelled with the FDTD and large perfectly conducting plates are modelled with the TD-UTD. All inhomogeneous bodies are enclosed in a so-called FDTD-volume and the thin-wire antennas can be embedded into this volume or can lie outside. The latter avoids the simulation of white space between antennas and inhomogeneous bodies. If the antennas are positioned into the FDTD-volume, their discretization does not need to agree with the grid of the FDTD. By using the TD-UTD large perfectly conducting plates can be considered efficiently in the solution-procedure. Thus this hybrid method allows time-domain simulations of problems including very different classes of objects, applying the respective most appropriate numerical techniques to every object.

scholarly journals Application of Time-Domain Full Waveform Inversion to Cross-Hole Radar Data Measured at Xiuyan Jade Mine, China

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3114 ◽  
Author(s):  
Sixin Liu ◽  
Xintong Liu ◽  
Xu Meng ◽  
Lei Fu ◽  
Qi Lu ◽  
...  
Keyword(s):  
High Resolution ◽  
Ray Tracing ◽  
Time Domain ◽  
Waveform Inversion ◽  
Synthetic Data ◽  
Radar Data ◽  
Liaoning Province ◽  
Full Waveform Inversion ◽  
Full Waveform ◽  
The Time Domain

Xiuyan Jade, produced in Xiuyan County, Liaoning Province, China is one of the four famous jade in China. King Jade, which is deemed the largest jade body of the world, was broken out from a hill. The local government planned to build a tourism site based on the jade culture there. The purpose of the investigation was to evaluate the stability of subsurface foundation, and the possible positions of mined-out zones to prevent the further rolling of the jade body. Cross-hole radar tomography is the key technique in the investigation. Conventional travel time and attenuation tomography based on ray tracing theory cannot provide high-resolution images because only a fraction of the measured information is used in the inversion. Full-waveform inversion (FWI) can provide high-resolution permittivity and conductivity images because it utilizes all the information provided by the radar signals. We deduce the gradient expression of the time-domain FWI with respect to the permittivity and conductivity using a method that is different from that of the previous work and realize the FWI algorithm that can simultaneously update the permittivity and conductivity by using the conjugate gradient method. Inverted results from synthetic data show that time-domain FWI can significantly improve the resolution compared with the ray-based tomogram methods. FWI can distinguish targets that are as small as one-half to one-third wavelength and the inverted physical values are closer to the real ones than those provided by the ray tracing method. We use the FWI algorithm to the field data measured at Xiuyan jade mine. Both the inverted permittivity and conductivity can comparably delineate four mined-out zones, which exhibit low-permittivity and low-conductivity characteristics. Furthermore, the locations of the interpreted mined-out zones are in good agreement with the existing mining channels recorded by geological data.

scholarly journals Kramers–Kronig Relations – Supplementary Technique to the Time-Domain Spectroscopy

2020 ◽  
Vol 65 (12) ◽  
pp. 1051
Author(s):  
V.S. Ovechko
Keyword(s):  
Wave Equation ◽  
Time Domain ◽  
Simultaneous Measurement ◽  
Dispersion Medium ◽  
Measurement Method ◽  
Ultra Wideband ◽  
Time Domain Spectroscopy ◽  
Optical Signals ◽  
The Time Domain ◽  
Further Development

We have proposed a new method for obtaining the Kramers–Kronig relations based on the analysis of the earlier proposed solution of the wave equation for a dispersion medium [2]. The use of this solution for ultra-wideband (femtosecond) optical signals allowed us to propose a simultaneous measurement method for both n (w) and k (w). The latter is a further development of the time-domain spectroscopy method.

A novel FGCPW-fed flag-shaped UWB monopole antenna

2015 ◽  
Vol 8 (2) ◽  
pp. 319-326 ◽  
Author(s):  
Ayman S. Al-Zayed ◽  
V.A. Shameena
Keyword(s):  
Time Domain ◽  
Parametric Analysis ◽  
Coplanar Waveguide ◽  
Monopole Antenna ◽  
Ultra Wideband ◽  
Simple Design ◽  
Operating Range ◽  
Antenna Performance ◽  
Compact Size ◽  
The Time Domain

A finite-ground coplanar waveguide (FGCPW)-fed compact ultra-wideband flag-shaped monopole antenna is presented. The antenna consists of a FGCPW-fed monopole asymmetrically loaded with a rectangle strip. The antenna has a compact size of 21.85 × 28 × 1.6 mm3. Parametric analysis is conducted to understand the effect of various parameters on the antenna performance. Simple design equations are presented to provide reliable initial design of the antenna if a different substrate is to be used. Constant gain and monopole-like radiation patterns are observed along the entire operating range from 3.1 to 12 GHz. Investigation of the time domain characteristics reveals that the proposed antenna exhibits excellent pulse handling capabilities.

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