Terrain radiation: Measurement investigation at 94 GHz

Using the 94 GHz — radiometers situated on board of a helicopter and on a measuring tower, there were investigated radiating properties of various surface types of soil and sea under their different states and season-weather conditions. The measurements were accompanied with controlling biogeophysical parameters of the surfaces and atmosphere. The plotted dependencies and the interrelations noticed in the process of discussion of the results of our work may be used when working out and estimating efficiency of the operation algorithms of the systems providing remote sensing of the surround medium.     

Outdoor-to-Indoor Office MIMO Measurements and Analysis at 5.2 GHz

The outdoor-to-indoor wireless propagation channel is of interest for cellular and wireless local area network applications. This paper presents the measurement results and analysis based on our multiple-input-multiple-output (MIMO) measurement campaign, which is one of the first to characterize the outdoor-to-indoor channel. The measurements were performed at 5.2 GHz; the receiver was placed indoors at 53 different locations in an office building, and the transmitter was placed at three "base station" positions on a nearby rooftop. We report on the root-mean-square (RMS) angular spread, building penetration, and other statistical parameters that characterize the channel. Our analysis is focused on three MIMO channel assumptions often used in stochastic models. 1) It is commonly assumed that the channel matrix can be represented as a sum of a line-of-sight (LOS) contribution and a zero-mean complex Gaussian distribution. Our investigation shows that this model does not adequately represent our measurement data. 2) It is often assumed that the Rician if-factor is equal to the power ratio of the LOS component and the other multipath components (MPCs). We show that this is not the case, and we highlight the difference between the Rician if-factor often associated with LOS channels and a similar power ratio for the estimated LOS MPC. 3) A widespread assumption is that the full correlation matrix of the channel can be decomposed into a Kronecker product of the correlation matrices at the transmit and receive array. Our investigations show that the direction-of-arrival (DOA) spectrum noticeably depends on the direction-of-departure (DOD); therefore, the Kronecker model is not applicable, and models with less-restrictive assumptions on the channel, e.g., the Weichselberger model or the full correlation model, should be used.     

Characterization of Vehicle-to-Vehicle Radio Channels from Measurements at 5.2 GHz

The development of efficient vehicle-to-vehicle (V2V) communications systems requires an understanding of the underlying propagation channels. In this paper, we present results on pathloss, power-delay profiles (PDPs), and delay-Doppler spectra from a high speed measurement campaign on a highway in Lund, Sweden. Measurements were performed at a carrier frequency of 5.2 GHz with the communicating vehicles traveling on the highway in opposite directions. A pathloss coefficient of 1.8 shows the best fit in the mean square sense with our measurement. The average root mean square (RMS) delay spread is between 263 ns and 376 ns, depending on the noise threshold. We investigate and describe selected paths in the delay-Doppler domain, where we observe Doppler shifts of more than 1,000 Hz.     

Slot Antenna Array with Integrated Filter for WLAN Application at 5.2 GHz

This paper deals with the design of a \(2\times 2\) Integrated Filter Antenna array working at 5.2 GHz for IEEE 802.11a WLAN application. The filtering action is incorporated into the conventional antenna array, rendering enhanced selectivity and sharper gain roll-off than the conventional approach. An equivalent circuit model is extracted to validate the working of the proposed design. Fractional band width of \(3.0\%\) around 5.2 GHz (ranging between 5.15 and 5.31 GHz) and maximum gain of 11.11 dBi is obtained through this design.     

工作于2.4GHz/5.2GHz双频段微带缝隙天线的设计

设计了一款可应用于WLAN无线通信设备上的新型结构缝隙天线,该天线采用在贴片上开槽加载和微带线馈电等方法使其可工作在WLAN的2.4GHz/5.2GHz双频段上。通过高频仿真软件HFSS对天线进行的仿真结果比较理想,实测结果表明该天线覆盖了WLAN所需要的频率带宽为2.4000～2.4836GHz和5.15～5.35GHz。     

广州地区33．5GHz和93GHz降雨传播特性测量

本文给出了１９９２年７—９月份广州地区Ｏ．４ｋｍ地面电路３３．５ＧＨｚ和９３ＧＨｚ雨衰减测量结果及雨衰减和降雨率短期统计结果之间的关系，并利用这一结果和长期降雨率统计对雨衰减预报作了初步探讨。同时分析了３３．５ＧＨＺ和９３ＧＨＺ雨衰减频率换算关系。文中还导出了雨致交叉极化鉴别度（ＸＰＤ）与实测差分衰减和差分相移之间的理论关系。在８ｍｍ波段可忽略差分相移的情况下，给出了利用３３．５ＧＨｚ部分实测差分衰减计算的ＸＰＤ结果，并与理论模式预测值作了比较。     

Linear dependence of double-directional spatial power spectra at 2.4 and 5.2 GHz from indoor MIMO channel measurements

Multiple-input multiple-output (MIMO) double-directional spatial channel responses for co-located indoor measurements at 2.4 and 5.2 GHz using eight element uniform circular arrays are compared. Correlation coefficients of the power spectra demonstrate a linear dependence, indicating similarity in propagation mechanisms at the two frequencies.     

Predicted HIPERLAN coverage and Outage performance at 5.2 and 17 GHz using indoor 3-D ray-tracing techniques

The European Telecommunications Standards Institute (ETSI) has recently defined a European standard for High Performance Radio LANs. This standard, known as HIPERLAN, has dedicated spectrum in both the 5 GHz and 17 GHz frequency bands. The system has been designed as an indoor wired-line replacement offering raw data rates in excess of 20 Mb/s.In this paper, simulated propagation data at 5.2 GHz and 17 GHz has been generated for a typical HIPERLAN environment. The analysis was performed using an indoor three dimensional ray-tracing algorithm developed for site specific single floor environments. The model is capable of predicting narrowband (power) and wideband (time dispersion) characteristics even in non-line-of-sight locations.Using this propagation information, the design of a suitable equaliser and the expected coverage of a HIPERLAN node is investigated for a particular indoor location. Emphasis has been placed on the need to develop low cost and robust receiver designs that are compatible with the design goal of a small and low power terminal.     

常见室内建筑材料5.8 GHz电参数测量研究

室内无线电通信的研究必须要知道室内建筑材料的电参数,对内装金属丝的强化玻璃、塑料板墙和木制门等常见室内建筑材料在5.8GHz的反射系数、透射系数和介电常数进行了测量和理论计算.测量结果和理论计算结果非常一致.在对测量结果处理时,使用了时间门限(Time Gating)技术来消除周围环境的影响.     

Measurements at 2.4, 3.4, 5.2, 28 and 60 GHz for Device-to-Device Wireless Communications

Wireless Personal Communications - Wireless communication networks with increased demand for higher speed in data transfer have paved way for device-to-device (D2D) wireless communications. This...     

Measurement of extinction cross-section of single particles at 100 GHz

The extinction cross-section of single particles of dimensions comparable with the wavelength has been measured using a double resonance technique at 100 GHz. Results agree well with Mie's theory. The technique is applicable to moving particles with velocities up to a few metres per second.     

Monostatic Reflectivity Measurement of Radar Absorbing Materials at 310 GHz

This paper presents monostatic reflectivity measurements of radar absorbing materials at 310 GHz in a phase-hologram-based compact range. The radar cross-section method was used and the backscattered reflection was measured with horizontal and vertical polarizations in plane-wave conditions. Transmission was also studied. The reflectivity was measured over an incidence angle of 0$^circ$–45$^circ$. The reflectivity of Thomas Keating Terahertz RAM at normal incidence was found to be$-$56 dB—the smallest of the studied materials. The reflectivity of carpet material measured was also below$-$40 dB and it was found to be suitable for use as an absorber. The results are in line with those available from previous studies of reflectivity and complement them with new materials, frequency, and angle information.     

Measurement for dielectric properties of organic liquids at 890 GHz

An automatic measurement system using two-beam interferometer has been used to measure dielectric properties of organic liquids at 890 GHz. The sample cell with fixed length and plane parallel windows was adopted. The influence of phase-shift and absorption coefficient causing by multiple reflection was eliminated by theory. The measuring results of refractive index and absorption coefficient of some kinds of organic liquid are given.     

Measurement of the complex refractive index of concrete at 57.5 GHz

The complex refractive index of concrete is measured at 57.5 GHz by the combined use of free-space reflection and transmission methods. The measured refractive index of the concrete 14 months after concreting was 2.55-j0.084. This index, in particular the imaginary part, is sensitive to the curing time after concreting and the water content. The transmission coefficient of a concrete plate, mainly determined from the imaginary part of the complex refractive index, is less than -20 dB/cm when the concrete is fresh and moist and reaches -9 dB/cm after aging for fourteen months. In contrast, the reflection coefficient of a concrete plate is less dependent on water content     

Measurement of the Odin telescope at 119 GHz with a hologram-typeCATR

Development work of a 119 GHz compact antenna test range (CATR), based on a 2.4 m×2.0 m hologram and its application on the Odin telescope tests are described. The hologram element comprises seven parts, which are fabricated using silk-screen printing techniques. Comparison between the theoretical and the measured quiet-zone fields of the hologram CATR is made, which demonstrates the correctness of the analysis method and also the importance of high quality physical joints between the hologram parts. The CATR has been successfully used in the measurement of a 1.1-m offset reflector antenna onboard the Odin spacecraft. The measured and calculated antenna radiation patterns are in good agreement in the main beam region. The effects of the imperfections in the quiet-zone field and in the aperture field of the antenna on the measurement results are simulated     

Measurement on the dielectric properties of acid-doped ice at 9.7GHz

The relative complex dielectric permittivity of acid-doped ice was measured at 9.7 GHz with the standing wave method. The objective of this measurement is to clarify the basic physical properties of ice necessary for the microwave remote sensing of the cryosphere. The acid-doped ice was investigated because acid is one of the major impurities found in snow and ice in the cryosphere. The experimental results show that the complex permittivity increases linearly with concentration of doped acid. Moreover, when the concentration of acid is expressed by molarity, this linear relation is independent of the sort of acid. The complex permittivity of acid-doped ice can be expressed as a function of concentration of acid and temperature definitely. A possible mechanism for enhancing the complex permittivity of acid-doped ice is formation of liquid phase in ice     

Measurement of extinction cross-sections of dry and wet ice spheres at 35 GHz

Measurements at 35 GHz of the extinction cross-sections of sets of particles of ice simulating dry and wet hail are reported. An open-resonator system was used. Results are compared with values calculated by applying Mie's theory to spherical particles having a simple composition.     

Propagation Loss Measurement of Wireless Body Area Network at 2.4 GHz and 3.35 GHz Bands

The main purpose of this work is to measure and analyze the propagation loss of the Wireless Body Area Network (WBAN) in frequency and time domain at two frequency bands, namely 2.4 GHz band with 80 MHz bandwidth and 3.35 GHz band with 500 MHz bandwidth. Four different scenarios (front to front, front to back, front to off-body node and back to off-body node) using many antenna´s locations on the body are used to investigate the channel response (path loss) of WBAN. It is found that the front to front channels and the front to off-body node channels have a low fading. The front to back channels and the back to off-body node channels have a high fading that can be approximated by the Distorted Rayleigh fading. Thus the WBAN range for the front to off-body node scenario is more than the range of the back to off-body node scenario.

     

6.0-6.4GHz室内MIMO无线信道测量与传播特性分析

工作在6GHz以上高频段的多输入多输出(Multi-Input-Multi-Output,MIMO)无线通信系统是下一代无线移动通信的有力竞争方案.目前,对制约无线系统性能的高频段空时无线信道特性研究仍较少见.针对这一现状,采用基于网络分析仪的信道测量平台对典型办公环境下6.0-6.4GHz MIMO无线信道特性进行测量和分析.为了明确高频段为系统设计带来的新问题,将测量得到的高频段MIMO信道特性参数与低频段对比.对比结果表明,6.2GHz频段与2.45GHz频段MIMO信道传播特性存在较大差异.在对6.0-6.4GHz室内覆盖MIMO无线通信系统进行设计和评估时,需要基于6.0-6.4GHz频段无线信道传播的新特性对系统的关键技术和方案进行调整.     

Measurement of permittivity of aqueous solutions at 44 GHz by FM receiver

An instrument using a variable-thickness waveguide cell has been developed for measurement of absolute complex permittivity at 44 GHz. The superheterodyne is used to rise the sensitivity. The results of measurements of water and saccharose aqueous solutions in the range of 15–27 °C are presented.