Polarization Signal Processing Research Articles

Electromagnetic Performance of Waveguide Polarizers with Sizes Obtained by Single-Mode Technique and by Trust Region Optimization

Modern wireless networks, stationary terrestrial and satellite systems use many modern technologies to increase communication channels information capacity. They save limited frequency resources. In satellite communications the polarization signal processing is applied to reuse the allocated frequency bands. Usage of circularly polarized electromagnetic waves, which transmit useful signals, reduces fading effects and eliminates disadvantages introduced by multipath propagation interferences. In this case the distortion levels for signals with an odd number of electromagnetic waves reflections in the receiving antenna systems will be reduced down to the thresholds of their cross-polarization isolation. Besides, in the case of orthogonal polarizations usage, the achieved information capacity of the applied wireless communication channel multiples almost by the factor of two. The type of polarization of the used electromagnetic wave strongly determinates the peculiarities of the process of its propagation in the space or transmission line. Polarization signal processing is frequently carried out in horn feed systems of the reflector antennas. Such feed networks and systems allow to transmit and receive signals with several kinds of polarization at the same time. The fundamental element of dual circular polarization antenna feed networks is a waveguide polarization duplexer. The phase, isolation and matching characteristics of a polarization converter strongly influence on the functionality and polarization discrimination possibilities of the entire reflector antenna system. Therefore, the development and optimization of the characteristics of waveguide polarizers for satellite communication antennas is a crucial technical problem, which must be solved by fast and accurate methods. The comparison of electromagnetic performance of waveguide polarizers with sizes obtained using a fast single-mode technique and by more accurate trust region optimization method is carried out in this research. The results for differential phase shift, level of voltage standing wave ratio, ellipticity coefficient and cross-polarization discrimination are shown and discussed.

Регульований поляризатор на основі квадратного хвилеводу із діафрагмами та штирями

Polarization signal processing is widely used in modern information and telecommunication systems for various purposes. Signal polarization processing is carried out in polarization-adaptive antenna systems. The key element of such systems is transformation devices for polarization processing. They perform the transformation of the types of polarization and separate the different types. The most commonly applied systems are the ones using a single circular polarization or two orthogonal circular polarizations simultaneously.The absence of the need for an accurate angle orientation between the transmitting and receiving antennas to establish communication is one of the basic advantages of this type of polarization. When using antenna systems with linear polarization, signal losses appear due to inconsistency in the orientation of the polarization planes of the transmitting and receiving antennas. This feature of circular polarization is important for satellite and many other telecommunications systems. In such systems it is difficult to maintain a fixed orientation of one antenna relative to the other. In addition, circular polarization is used to communicate with satellites orbiting the direction of the radio link. Regardless of antenna orientation, when using circular polarization, the received signal level is constant. These advantages explain why circular polarized antennas are widely used in radio engineering systems for various purposes. The paper presents the results of the development of a polarization device based on a square waveguide with two posts and two diaphragms in the frequency range from 7,7 to 8,5 GHz. The article contains the results of calculations using the developed mathematical model of the device. In addition, the results of modeling the device using the finite element method are presented for comparison. A comparison was made of the polarization characteristics and the match of the developed polarizer. The created mathematical model makes it possible to effectively analyze the characteristics when changing design parameters. These parameters include the size of the wall of the square waveguide, the heights of the diaphragms and pins, the distance between them, the thickness of the diaphragms and pins. The developed polarizer is suggested for the application in satellite telecommunication and radar systems.

Optimization of a polarizer based on a square waveguide with irises

Antenna systems with polarization signal processing are key element of modern satellite telecommunications systems. In such systems polarization processing is performed by waveguide polarizers. Thus, the development of the design of new polarizers, the creation of new methods for their analysis and optimization are important problems. Waveguide polarizers with irises are the most efficient and technologically advanced in manufacturing. Moreover, they provide wide bandwidths. Optimization of the electromagnetic characteristics of a waveguide polarizer with irises is the goal of the study. To achieve this purpose, we solve the problem to create a new mathematical model, which makes it possible to analyze the influence of the polarizer design parameters on its electromagnetic characteristics. In the investigation a model of a waveguide polarizer with irises was created using the theory of microwave circuits. A new analytical model of such a polarizer has been developed using a general wave scattering matrix. The main characteristics of the waveguide polarizer were determined through the matrix elements. In this work the optimization of characteristics of a polarizer based on a square waveguide with irises has been carried out in Ku-band 10.7–12.8 GHz. The presented mathematical model of such a polarizer allows to take into account the heights of the irises, the distances between them and their thicknesses. The results obtained show that the proposed model is simpler for calculation of the electromagnetic characteristics in comparison with the finite integration technique, which is used to analyze microwave devices for various purposes.

Компактний хвилевідний поляризатор із трьома протифазними штирями

Nowadays one of the fundamental problems is the economy of digital information and frequency resources. The introduction of modern telecommunication systems and 5G networks requires the search for fundamental methods to save and reuse frequency resources. To save the frequency resource in modern communication systems the new technologies for the increase of the information capacity of communication channels are used. Antenna systems with polarization signal processing are applied for this purpose. Such systems allow transmitting signals with different types of polarization. The application of the electromagnetic waves with orthogonal polarizations improves the information characteristics of radio systems for various purposes. This makes it possible to double the information capacity of satellite communication channels. In addition, such processing is carried out in meteorological and radar systems for receiving, transmitting and processing of the information. The key devices of such systems are polarizers and orthomode transducers. The electromagnetic characteristics of these devices affect the overall system performance. The electromagnetic characteristics include phase, matching and polarization characteristics. The article presents the results of the development of an adjustable polarizer based on a square waveguide with three posts. The developed polarizer operates in the X-band from 8,0 GHz to 8,5 GHz. The mathematical model of such a device is based on the scattering and transmission wave matrix. The characteristics of the model were obtained through the elements of this matrix. To check the correctness of the developed model, a model based on the finite integration method was also created. This method is often used to simulate microwave devices. The developed polarizer based on a square waveguide with three posts allows regulating its matching and polarization characteristics by changing the length of the posts. Such devices are characterized by small transverse dimensions and stability of the polarization transformation parameters.

PEACE: Polarization Enabled Active Cooperation Scheme Between Primary and Secondary Networks

In this paper, we present a two-phase cooperative transmission and relay scheme between a primary network and a secondary network to address spectrum underutilization and spectrum inefficiency. By placing orthogonally dual-polarized antennas (ODPAs) and enabling polarization signal processing functionalities at secondary users (SUs), the cochannel interference caused by multiple independent transmissions from primary and secondary networks can be mitigated. A framework design, including system description, signaling plan, and key enabling techniques, is studied to perform Polarization Enabled Active CoopEration (PEACE) between primary users (PUs) and SUs. In the presented PEACE framework, polarization zero forcing and oblique projection polarization filtering are utilized to address interference from SUs to the primary network and to separate SUs signals, respectively. We provide theoretical analysis to maximize the sum achievable channel capacity under certain transmission rates and power constraints to evaluate PEACE performance. To solve the original nonconvex optimization problem, it is effectively approximated to a convex problem, which can be tackled quite efficiently. Closed-form solutions to optimal power allocation of SUs are, respectively, obtained by a centralized algorithm and a distributed algorithm. Extensive numerical results are given to illustrate the performance and to examine the features of the PEACE framework and the proposed algorithms.

Signal processing method of a novel polarized array radar seeker

This paper proposes a novel polarized radar seeker based on the polarized antenna array. A fully polarized signal processing method for the proposed radar seeker is studied under the environments with electromagnetic interferences. A dual polarized antenna array is employed to transmit and receive the radar signals. The instantaneous polarization signal processing technique is used to detect and recognize the targets. The direction of arrival(DOA) of the target is measured through the spatial spectrum with high resolution for the polarized array radar seeker system. The fully polarized signal model of the polarized array radar seeker is formulated and a specific signal processing algorithm is expounded. The theoretical research and numerical simulation results demonstrate that the proposed radar seeker has good performances in target detection and electronic warfare. The research results can provide an effective technical approach to develop and research the new generation radar seeker.

On exploiting polarization for energy-harvesting enabled cooperative cognitive radio networking

Radio spectrum underutilization and energy inefficiency become urgent bottleneck problems to the sustainable development of wireless technologies. The research philosophies of wireless communications have been shifted from balancing reliability-efficiency tradeoff in the link level to seeking spectrum-energy efficiency in the network level. Global spectrum-energy efficient designs attract significant attention to improving utilization and efficiency, wherein cognitive radio networks and energy scavenging related techniques are of particular interests. In this article, we first provide a systematic study on cooperative cognitive radio networking (CCRN), followed by the discussions on research issues and challenges in designing spectrum-energy complexity efficient CCRN. As an effort to shed light on addressing spectrum-energy inefficiency at a low complexity, a novel CCRN paradigm exploiting polarization and energy harvesting capabilities is elaborated. Specifically, we present a novel polarization and energy harvesting based framework for achieving size-cost effective CCRN. We introduce polarization signal processing to avoid interference between secondary users and primary users in cooperation. We propose a weighted sum spectrum efficiency based problem formulation and multi-timescale dynamic programming based energy/power allocation policy to evaluate the cooperation performance, subject to energy levels, power, and throughput constraints.

A 1 /spl times/ 2 variable optical power splitter development

The possible applications and various designs of variable optical power splitters (OPSs) in the past years have been discussed in this paper. A new design based on polarization signal processing to realize the variable OPS is proposed. The measured result of the built prototype shows that it is a practical design