Ka-band Communication Systems Research Articles

Principles of creating a phased active antenna array for mobile satellite terminals based on a multilayer printed circuit board

The paper describes concept of the phased array antenna made on a multilayered printed circuit board for the subscriber terminal of a modern Ka-band mobile communication system. Two options of the array are considered: Rx- and Tx- arrays. The architecture of the PAA is described, and main problems arising when creating such antennas are discussed. The ways of their solution are offered. The multilayer printed radiator is described in details. The proposed concept will be useful for design of the phased array antenna experimental model.

Ka-Band Dual-Frequency Single-Slot Antenna Based on Substrate Integrated Waveguide

This letter presents a novel dual-frequency single-slot antenna in Ka-band based on a substrate integrated waveguide (SIW). From the view of an SIW resonator, the single-slot cuts currents of the TE101 and TE102 mode in two frequencies, respectively, which leads to a dual-frequency performance. In addition, the difference between two resonance frequencies may be tuned by varying the length of the SIW, which changes the resonant frequencies of the two modes. Three antennas operating from 25.3 to 30.7 GHz with gain greater than 6 dBi are designed and fabricated. Simulated and measured results of the antennas are presented as well. The results show that the proposed antennas achieve stable tunable dual-frequency performance, which may be applied to a Ka-band communication system.

The Selection of Transmitter Elevation in a Ka-Band HAP-Based Communication System under Fog Attenuation

The Rayleigh approximation model is used for analyzing fog attenuation of the HAP-based communication system, the influence of transmitter elevation to fog attenuation under different temperature and liquid water density are studied, Numerical results show the optimum transmitter elevation angle in a ka-band HAP-based communication system under fog attenuation.

Derivation of Microwave Refractive Index Structure Constant <formula formulatype="inline"><tex Notation="TeX">$(C_{n}^{2})$</tex> </formula> of the Atmosphere From K-Band Interferometric Phase Measurements

Differential phase data has been collected using a site test interferometer (STI) at K-band for several years at various NASA ground station sites, including the NASA Deep Space Network (DSN) in Goldstone, CA, and the NASA Space Network (SN) sites in White Sands, NM, and Guam. An objective of this work is to characterize the site-dependent atmospheric phase stability to determine the viability of that site for arraying applications. A useful figure of merit to quantify this effect is the determination of the microwave refractive index structure constant, C n 2 , which is highly dependent on variations in the water vapor concentration of the troposphere. In this paper, a method is proposed to derive C n 2 from a two-element site test interferometer utilizing temporal phase structure function information. In this way, a path-averaged C n 2 at each ground station site is determined which can be used in the design and expected system performance of future Ka-band communication systems in an arrayed architecture. Statistical characterization of microwave C n 2 indicates that a mean value of 2.04 ×10 -14 , 2.08×10 -14 , and 9.8×10 -13 is expected for Goldstone, CA, White Sands, NM, and Guam, respectively.

Ka-band High-speed Communication Systems on Small Satellites for Future Advanced Communication Networks and Earth Observations

The goal of this paper is to describe the capabilities and application methods of Ka-band communication systems for small satellites indicating contributions to future advanced communication networks and Earth observations. This study is based on the actual experience on the design of the Ka-band high-speed communication system of the small satellite Flying Laptop, which is developed at the Institute of Space Systems of the Universitat Stuttgart. The objectives of the Ka-band communication system is to demonstrate high-speed communications with a data rate of up to 500 Mbit/s as well as to conduct scientific Earth observations. Flying Laptop satellite is also equipped with a Ku-band signal transmitter. The attenuation of the two transmission signals in Ka-/Ku-bands are measured with ground stations to estimate the local precipitation rate. The mathematical background and operational scenario of this measurement is summarized. The received Ka-band transmission signal is measured in different meteorological conditions to identify attenuation characteristics of the Ka-band signal due to rain, clouds, trace gases and so forth, which is of great interest for utilization of Ka-band frequencies for future broadband communications.

Notice of Violation of IEEE Publication Principles: Ka-band distributed MEMS phase shifters on silicon using AlSi suspended membrane

Notice of Violation of IEEE Publication Principles<br><br>"Both the authors and the Editor-in-Chief of Volume 13, number 3 of the IEEE/ASME JMEMS (June 2004, pp. 542-549) of the paper numbered JMEMS 1041 have agreed that this paper, Ka-Band Distributed MEMS Phase Shifters on Silicon Using AlSi Suspended Membrane," should not have been published. The paper would have been withdrawn had this fact been discovered before the IEEE/ASME JMEMS print date for June 2004. The authors have indicated that they will work to provide a new version their paper that will be considered for publication if it is submitted in the future. For help in coming to this decision, I would like to thank those concerned individuals, including the authors, JMEMS editors, and highly respected researchers in the MEMS and microwave communities who contributed their time and consideration to help us assure the integrity of our journal." <br><br>Richard S. Muller, Editor-in-Chief, IEEE/ASME JMEMS<br><br>This paper presents the design, fabrication, and testing of distributed MEMS phase shifters for Ka-band communication systems. The phase shift can be obtained by changing MEMS bridge capacitors located periodically over the transmission line. Simulation results of phase shifters with various structural parameters are analyzed to develop the optimized designs. The phase shifters are fabricated on the high-resistivity silicon substrate, using suspended AlSi bridge membrane. The measured results demonstrate a phase shift of 286° at 36 GHz with the actuation voltage of 25 V, and a return loss better than 10 dB over 0-40 GHz band. In addition, lifetimes of 3×10/sup 6/ cycles have been achieved for the fabricated phase shifter with all MEMS bridges held to be valid. It shows that AlSi alloy has a nice compromise between strength and resilience. <br/> This paper presents the design, fabrication, and testing of distributed MEMS phase shifters for Ka-band communication systems. The phase shift can be obtained by changing MEMS bridge capacitors located periodically over the transmission line. Simulation results of phase shifters with various structural parameters are analyzed to develop the optimized designs. The phase shifters are fabricated on the high-resistivity silicon substrate, using suspended AlSi bridge membrane. The measured results demonstrate a phase shift of 286° at 36 GHz with the actuation voltage of 25 V, and a return loss better than 10 dB over 0–40 GHz band. In addition, lifetimes of 3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> cycles have been achieved for the fabricated phase shifter with all MEMS bridges held to be valid. It shows that AlSi alloy has a nice compromise between strength and resilience.

Miniature coplanar bandstop filter for Ka-band applications based on original resonant coupling irises topology

An original, low cost and miniature bandstop CPW filter, for front-end terminals of Ka-band satellite communications systems, has been implemented on a micromachined silicon membrane. Based on a resonant coupling irises topology, such a filter simultaneously achieves a high level of compactness, a high attenuation (at least 24 dB) in the uplink band and a very low insertion loss (close to 0.3 dB) in the downlink band.

A Compact Broadband PHEMT MMIC Power Amplifier for K through Ka-band Applications

A compact and broadband MMIC power amplifier operating from 18 GHz to 35 GHz is developed for K- through Ka-band applications implementing a rigorous electromagnetic (EM) simulation of closely spaced matching networks. The EM simulation results in a compact chip size as small as 2.16 mm × 2.0 mm and isolations of less than -25 dB up to 40 GHz between neighboring distributed structures. The two-stage balanced power amplifier fabricated using a 0.25 µm AlGaAs/InGaAs/GaAs PHEMT technology has an average gain of 11 dB, return losses less than -10 dB, and P1 dB above 20.5 dBm from 18 GHz to 35 GHz. This compact and broadband MMIC power amplifier is suited for power amplifiers for most K through Ka-band communication systems such as the FSS, LMDS, and ITS.

A three-site comparison of fade-duration measurements

Important elements in the design of Ka-band communication systems are the duration of fade and nonfade events at a particular fade depth. The choice of modulation and forward error correcting codes will depend on both the fading time dynamics and annual fade occurrence statistics. This paper examines the fade duration measured at locations in three of the Advanced Communications Technology Satellite (ACTS) propagation experimental regions, namely, Florida (rain zone N of the radiocommunications sector of the International Telecommunications Union ~ITU-R\ model), New Mexico State University (ITU-R rain zone M), and Alaska (ITU-R rain zone C). Within each region, measures of the underlying uniformity are described and an interregional comparison examines the ability to scale the local results.

The Ka-Band Communication Systems of the Lincoln Experimental Satellites LES-8 and LES-9

Introduction L INCOLN Experimental Satellites LES-8 and LES-9 are a pair of experimental communication satellites designed and built to operate in a synchronous ecliptic orbit and to communicate on a crosslink from satellite to satellite as well as with surface terminals. At synchronous-orbit altitude, each satellite has a groundvisibility area about 8000 miles in diameter. With crosslink communication between two satellites spaced thousands of miles apart, a single pair of satellites could provide communications among terminals anywhere in an area covering more than 3/4 of the surface of the Earth. Communication links are possible at both UHF and Ka-band at approximately 37 GHz. Figure 1 shows a cutaway drawing of LES-9. The side facing the Earth is the forward platform, which is used for mounting and precision alignment of the Ka-band antennas and the Earth sensors. The Ka-band receiver diplexer filters and front ends are mounted as close as possible to the diplexer polarizer mounted on each antenna. The Ka-band transmitter power amplifiers are mounted on sections of the internal decagon adjacent to the forward platform to minimize the length of the waveguide runs to the antennas. LES-8 and LES-9 each utilize two independent Ka-band communication systems (see Fig. 2). The Ka-dish system uses a fixed paraboloidal reflector in conjunction with a steerable flat reflector to provide a narrow beam, tracking antenna for crosslink or uplink/downlink communications. The Ka-horn system includes a fixed horn to provide a wide-beam antenna coverage. Local oscillator requirements for both systems are provided by a single Ka-band local oscillator. Each receiver subsystem features a broadband low-noise mixer utilizing Schottky-barrier diodes to achieve a typical system noise figure of less than 8 dB. Each transmitter includes an array of solid-state amplifiers which utilize IMPATT diodes, and delivers 0.5 W of power to the antenna. The transmitter signal is modulated at a lower frequency and is upconverted to Kaband using a mixer similar to that used in the low-noise receiver. This paper will discuss the Ka-band systems carried on LES8 and LES-9, which were built to demonstrate component and