Design Considerations for Over-Water Microwave Radio Links - A Case Study

Arabian Gulf region with its hot, humid and prolonged summer is known to be one of the most challenging environments for radio-wave propagation. Over-the-sea microwave radio links here face degradation and unpredictability in performance due to anomalous propagation, ducting and reflective effects of large water bodies. This paper presents microwave radio link design challenges in an offshore environment and the methods implemented to overcome these challenges in the context of specific project experience in offshore field areas. A baseline design for the links was established initially which was optimized during the course of the project and during on-site implementation. Several design changes to achieve the desired performance were evaluated and implemented in the field. Required microwave link availability and performance objectives were achieved as a result of collaborative efforts between the operating company, contractor and radio manufacturer over a multi-year period. Use of quadruple diversity, optimal selection of frequencies, judicious use of ATPC (Automatic Transmit Power Control) and use of optimal signal polarisation were some of the methods used to achieve the desired link availability and performance. While these are well-known methods in radio engineering, the particular combination(s) employed to realize the desired performance objectives are identified in the paper as a lessons-learnt exercise which can be of wider application in the petroleum industry in the Gulf region. Over-water wideband microwave links are generally considered unreliable in terms of performance for utilization in process control applications involving remote shutdown and other critical operations. However, the links referred to in this paper continue to serve the field control system applications till date.

Quiet-Filament Eruptions and Coronal Jets as Causes of Depressions in Microwave Radio Emission

Several solar events with different types of negative microwave bursts have been studied using data from different spectral ranges. The total radio flux data obtained at the Ussuriysk Observatory, the Nobeyama Observatory, the US Air Force Radio Solar Telescope Network (RSTN), and the spectropolarimeter of the Institute of Solar–Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS) were used. The images were analyzed using data from the SDO/AIA space observatory in the 304 Å channel and the Nobeyama radio heliograph at a frequency of 17 GHz. It was shown that the “isolated” depressions of radio emission were caused by the absorption of radiation from radio sources and/or vast regions of the quiet Sun by low-temperature material of a large eruptive filament in the absence of flares. This confirmed the conclusions of the previous studies. It was revealed that the cause of negative bursts of the “pre-burst depression” type was the screening of a near-limb radio source by the material of coronal jets. In the case of a weak flare accompanying the jet, the negative burst could also be of the “isolated” type. A case of a previously unreported occurrence of a deeper depression of radio emission at high frequencies as compared to low frequencies was considered. It was shown that negative bursts are not as rare phenomena as previously thought.

Simulation Charging of the Forming Line by the Operator Method

The application of repeated Laplace transform to the analysis of a line with distributed parameters is considered. As an example, pulse forming lines are analyzed, which are widely used in microwave radio devices and high-current charged particle accelerators. The results of the calculation of the charge voltage of the forming line from the voltage source are given. The dependence of the line charging mode on the relationship between the internal resistance of the source and the characteristic impedance of the line is shown.

Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System

This paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic parameters (absorption, reflection, transmission and homogenized permeability coefficients) have been determined. On the basis of simulation research, prototypes of electromagnetic field two-dimensional absorbers have been manufactured and verified experimentally in the proposed test system. The absorber has been implemented as a component of the low-cost energy harvesting system with a high-frequency rectifier and a voltage multiplier, obtaining usable DC energy from the electromagnetic field in certain frequency bands. The energy efficiency of the system has been determined and the potential application in energy harvesting technology has been assessed.

Antena Mikrostrip Array 8x2 Elemen untuk Aplikasi Radio Gelombang Mikro

ABSTRAKPeningkatan gain pada antena mikrostrip polarisasi melingkar menggunakan metode array 8x2 element diusulkan dalam penelitian ini. Antena yang diusulkan dirancang untuk bekerja pada rentang frekuensi 10700 – 11700 MHz untuk sistem komunikasi radio gelombang mikro. Untuk meningkatkan gain, antena yang diusulkan di optimasi menggunakan array dengan 8x2 elemen. Dari hasil pengukuran diperoleh nilai return loss -22.77 dB dan VSWR sebesar 1.156. Bandwidth yang dihasilkan dari antena array 8x2 elemen adalah 900 MHz dengan rentang frekuensi kerja 10700 MHz -11600 MHz serta impedansi sebesar 55.87 + j 4.97 Ω pada frekuensi kerja 10925 GHz. Gain dari antena array 8x2 elemen adalah 15.6 dB pada frekuensi kerja 10925 MHz. Optimasi dengan metode array 8x2 elemen berhasil meningkatkan Gain sampai dengan 47.76 % dibandingkan dengan desain array 4x2 element. Antena yang diusulkan cocok dijadikan kandidat untuk digunakan pada sistem komunikasi radio gelombang mikro.Kata kunci: antena, mikrostrip, gain, array, radio gelombang mikro ABSTRACTGain optimization on a circular polarization microstrip antenna using the 8x2 element array method is proposed in this study. The proposed antenna is designed to work in the frequency range 10700 - 11700 MHz for microwave radio communication systems. To increase the gain, the proposed antenna is optimized using an array with 8x2 elements. From the measurement results obtained return value of -22.77 dB and VSWR of 1,156. The Bandwidth produced from the 8x2 element antenna array is 900 MHz with a working frequency range of 10700 MHz - 11600 MHz and an impedance of 55.87 + j 4.97 Ω at a working frequency of 10925 MHz. The gain of the 8x2 element array antenna is 15.6 dB at a working frequency of 10925 MHz. Optimization with the 8x2 element array method succeeded in increasing Gain by up to 47.76% compared to the 4x2 element array design. The proposed antenna is suitable as a candidate for use in microwave radio communication systems.Keywords: microstrip, antenna, gain, array, microwave radio

Analysis of the probabilistic characteristics of the electrical parameters of a broadband balanced mixer of microwave radio signals based on resonant tunneling diodes and an assessment of its reliability

The object of research is the broadband balanced SHF mixer (BM) based on resonant-tunneling diodes (RTDs). The research goals are to perform the statistical analysis of BMs design parameters technological errors impact on its electrical characteristics scatter, and to analyze the kinetics of these characteristics under the destabilizing factors influence. The ranging of BMs design parameters technological errors impacts on its electrical characteristics scatter revealed that the biggest impact is made by the technological errors of the BMs non-linear elements I-V characteristics. The BMs reliability study revealed that to ensure the studied BMs reliability during operation under high temperatures impact the design and technological optimization of the BMs electrical characteristics is required.