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This paper describes short range UHF dual polarized, dual
frequency, radio propagation measurements performed in a forested
environment using low antenna elevations. The 2×2 polarization
matrix was investigated in terms of path loss, cross-polarization and
fading statistics. The results show a higher depolarization of the
vertical polarized signals...
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In this paper, we investigate the polarization characteristics of the multiple-input multiple-output (MIMO) channels. The cross polarization discrimination (XPD) is found to change over time, while its variation in frequency domain is relatively small. The probability density function (PDF) of the XPD follows a Gaussian distribution. Analysis and m...
The phase recovery scheme of a cross-polar interference cancellation (XPIC) system is considered here, assuming two completely independent RF transceiver chains for the two different polarizations. A novel Kalman based algorithm is proposed to jointly recover the phase of both the main polarization signal and the interfering one, at each single rec...
Citations
... In [6], the relation of the isolation and the arrangement of two nearby antennas with different operating bands in a cellular handset were studied. Antennas with reactive load [7] wavelength resonators such as electromagnetic band gap (EBG) structures [8,9] and defected ground structures (DGS) [10,11] and; lumped components [12]. Mushroom-like EBG structures are the ones that are usually inserted between patch antennas to prevent the propagation of surface waves for higher isolation and better radiation patters [13][14][15]. ...
A compact decoupling network for enhancing the ports isolation of two coupled antennas is proposed in this letter. Parallel coupled lines (PCLs) and transmission lines (TLs) with different electrical lengths are considered to control the magnitude and phase of this decoupling network, respectively. The coupling coe±cient of the PCLs is adjusted with various line widths and coupled gaps so that the magnitude of this network will be equal to that of the coupled antennas. And the electrical length of the series TLs can be controlled to make the signals of coupled antennas and decoupling network out of phase. Thus, the mutual coupling between the coupled antennas can be canceled. A prototype is fabricated on a RO4003 print circuit board (PCB) for demonstration. The measured results agree quiet well with the simulation ones. High antenna isolation and good matching are simultaneously achieved at the center frequency, i.e., 925MHz for global system mobile communications (GSM) which shows the compact decoupling network is suitable for reducing the isolation of size limited multi-antenna systems.
... The cross polarization discrimination (XPD), which is defined as the ratio of the amplitude of the orthogonally polarized component of the radio waves, produced by some propagation mechanism, to the amplitude of the original plane polarized waves, is found to be dependent on frequency as well as the separation distance between the transmitter and the receiver. Similar observation is also found in temperate forests by Kovacs et al. [48] at higher frequencies of 400 MHz and 1900 MHz. ...
A comprehensive review of radio wave attenuation in forest environments is presented in this paper. The classic analytical methods of propagation loss modeling and prediction are described flrst. This provides information on the physical processes that the radio waves undergo while propagating through a forest. The focus of this paper is on the review and summary of the experimental work done in this area and the development of empirical propagation loss prediction models. The propagation loss variation due to external factors such as antenna height-gain, depolarization, humidity efiect etc. are examined and discussed individually. In view of current research work done in this area, some possible future work is proposed to improve the performance of radio links in forest environment.
... The presented work is part of a major project aimed to describe the typical mobile-to-mobile radio propagation channels and the achievable performances in digital PMR systems [3], [4], [5]. ...
The mobile-to-mobile radio channel was investigated in different suburban outdoor-to-indoor environments. System performance parameters in terms of un-encoded BER and outage probability have been extracted from hardware and software TETRA simulations. In several scenarios, the measured signal envelope statistics were found to be a combination of single and double Rayleigh distributions. The system performances obtained in these scenarios were in general lower than the reference ETSI limits.
... The typical output power of a TETRA portable is 30dBm while the specified dynamic sensitivity level is -103dBm [4]. Based on the path-loss data in [5] and [6] signal attenuation of at least 120dB can be expected at practical distances considered in TETRA DMO. ...
... The work extends the results in [5], [6] introducing the BER evaluation/prediction in the radio channel characterization. ...
... The measurements were performed in a forest environment with a terrain geometry including small hills and valleys, similar to the ones investigated in [5], [6]. ...
This paper describes radio channel and BER investigations
performed in various scenarios typical to the TETRA direct mode
operation (DMO), in a forest area. The data from radio channel sounding
measurements was analysed in terms of average fade duration and envelop
CDF. The same data was used to evaluate the unprotected BER on a TETRA
communication link. The BER level distribution was compared to the
distribution obtained when simulating a pedestrian speed TETRA DMO radio
channel. The dynamics of the mobiles can have a strong influence on the
radio link quality. As a general tendency, higher practical BER values
can be expected as compared to the simulations when using the simple
TETRA radio channel model
Modern vehicles are having number of electronic gadgets inbuilt, which giving safety, luxury and comfort with entertainment. Most of the vehicles are having sophisticated entertainment devices with the advancements in the technology. The satellite digital audio radio service provides the high entertainment through high-fidelity audio network from the satellite to the passengers in the vehicles. Satellite data for entertainment like news, weather reports, traffic information and music will be available through monthly subscription to the users. A compact and low profile antenna was designed to receive these signals for providing digital audio radio entertainment in the vehicles. The antenna output parameters and its radiation pattern are presented in this paper.
A prediction model is created and presented in this paper to study the radiation level from mobile telephony base-station antennas using electromagnetic (EM) field simulation. The model concerns only the GSM antennas at 900 MHz. As an example, a residential apartment is chosen to be modeled and simulated using the method of moments, and compared with the on-site EM field measurement. As the three-dimensional model of the apartment has a size of 17.3 λ × 18.28 λ × 10.2 λ and is electrically large, the method of moments with higher-order basis functions and parallel computation are used to reduce the problem size and the computation time. The simulation results of the model shows a good agreement with the measurement results, and thus confirmed the model correctness. Also, based on the created model, the radiation level at any points in the apartment can be predicted and the results illustrated the whole region is within the radiation exposure threshold given by ICNIRP radiation safety standard.
This paper present the comparison of base station antenna operating at 900 MHz GSM network with 65° and 105° horizontal beamwidth. The base station antenna has a voltage standing wave ratio (VSWR) below 1.4, dual polarized, gain of around 16dB. Dipole antenna has been chosen due to its simplicity in antenna design and has been fabricated using brass. The dipole antennas are slanted to either +45° or -45° to increase the base station antenna sensitivity and the user capacity of a base station. The VSWR of the base station antenna was measured by using Agilent 8722ES Network Analyzer and the radiation pattern was done in Anechoic Chamber in Multimedia University, in Cyberjaya, Malaysia.
This paper present the design and development of base station antenna operating at 900 MHz GSM network. The base station antenna has a voltage standing wave ratio (VSWR) below 1.4, dual polarized, 16dB gain and horizontal beamwidth of 105 degree. Dipole antenna has been chosen due to its simplicity in antenna design and has been fabricated using brass. The dipole antennas are slanted to either +45 degree or -45 degree to increase the base station antenna sensitivity and the user capacity of a base station. This slanted feature is called X-Polarized or cross polarized. Feed network channel the radio frequency (RF) power equally to the antenna elements in the array. The VSWR of the base station antenna was measured by using Agilent 8722ES Network Analyzer and the radiation pattern was done in Anechoic Chamber in Multimedia University, in Cyberjaya, Malaysia. The field test measurement was done in a GSM900 base station site in Selangor, Malaysia.
The dependence of channel capacity on cross-polarization and the branch power ratio is established over a wide range of both realistic and idealized values. An existing empirical model is adjusted to avoid self-contradictory results for cross-coupled, but uncorrelated energy. Typical ranges are highlighted for realistic channel measurements from the literature, and extreme cases are identified. The value of a peak capacity measure is established and compared with the outage and average capacities. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1384–1388, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23360
