Planck satellite 70 GHz receiver noise tests

The LFI (Low Frequency Instruments) receivers in the coming Planck satellite are of continuous comparison type and use low noise amplifiers based on high electron mobility transistors manufactured from indium phosphide substrate (INP-HEMT-MMIC-LNAs). This article describes the 1/f-noise tests and the associated test system for the 70 GHz demonstrator receiver, which can either use single or dual channel phase switcher methods. The 1/f knee frequency is shown to depend on the calculation method of the r-value. A minimum 1/f knee frequency around 10 mHz has been achieved with full two channel foxtrot and individually adopted r-values for each phase states while a straightforward single phase technology cannot go below 40 mHz     

Mobile terminal location for UMTS

Interest in mobile phone location is expanding due to the implementation of the third generation (3G) multimedia phones. The initial need for accurate terminal positioning has been motivated by government authorities, mainly by the US FCC's E911 mandate for emergency services. In Europe, similar ideas have appeared but the primary interest is in commercial value-added functions. Systems resembling air navigation and secondary radar as brought down to street level and pedestrian speeds are also foreseen. This article presents an overview of UMTS mobile terminal location. The performance of standardized observed time difference of arrival (OTDOA) and a novel database correlation method (DCM) for wide bandwidth systems are evaluated through simulations in an urban microcell environment. DCM is shown to provide a reasonable location error of 25 m for 67% of the calls. The obtained respective OTDOA accuracy is 215 m only. Location problems encountered in built-up areas and relevant applications based on the obtained accuracy are discussed.     

Advanced measurement of rotor vibration in electric drives

The combination of microelectronic acceleration transducers and an RF telemetry link can provide a reliable means of measuring shaft vibrations of electric drives. Clear advantages include the possibility of installing the instrumentation into currently existing motor systems without any need to use flexible couplings or mounts. The proposed system covers frequencies up to several kilohertz and can handle torque transients of 20 Nm with a typical uncertainty of 1%. The preliminary system is extendable to cover adaptive control of dynamic drive performance and can be customized to specific speed and torque ranges     

Small Ku-band phased array antenna system

A four-element phased array antenna prototype with varactor tuning has been constructed. The design employs aperture-fed quarter-wave patch elements and loaded-line phase shifters, having a phase adjustment range of about 50/spl deg/, which enables beam steering up to 13/spl deg/ from the array boresight. The system is suitable as a building block for larger arrays and shows as such a maximum gain of 7.7 dBi and an impedance bandwidth of 1 GHz. The sidelobe level is better than -13 dB. Problems encountered include parasitic resonances which disturb matching, and partially deteriorate the radiation pattern. Additionally, mechanical manufacturing tolerances of the microstrip boards were not always adequate, whereby a 6% shift in the center frequency, some impedance errors, and phasing inaccuracies were observed.     

Base station antenna systems with built-in processing for thereduction of the effects of hardware imperfections

The effects of many mechanical and electrical manufacturing imperfections of antenna arrays can be minimized with an internal pattern database. Such deficiencies are the non-idealities of amplitude and phase characteristics of sub-arrays and active modules. The idea of the suggested method is to store measured pattern characteristics into the antenna's internal memory at delivery and later, during operation, to use this data to support, for example, a beam forming algorithm, or just to create a static optimum. Thus, the antenna "knows" its behaviour. This method is both more cost-effective than a fine tuning of the hardware items on the production line, and often, the only choice, if relatively inaccurate sheet metal antennas are considered; but naturally, requires some active RF hardware. Our tests demonstrate S-band patterns within 2 dB or 3° of the theoretical ones if an EPROM database at 1° intervals is used. The improvement of the depth of wanted minima can exceed 12 dB     

Low-cost ground-to-ground mobile telemetry link

A frequency modulated UHF telemetry link giving 5 MHz of baseband capacity with carrier to noise ratio exceeding 30 dB is described. The system is intended for ground mobile use and provides more than 1 km of coverage also in moderately obstructed terrain indicating allowable maximum path loss up to 110 dB. The mobile transmitter end uses a sturdy flexible antenna. Typical sensor signals include voltage outputs from accelerometers, strain gauges, and thermistors, but live broadcasting-quality television is also easy to implement. Digital interfacing is accomplished through suitable D/A converters, multiplexers, and coders. Both the transmitter and receiver utilize commercial-off-the-shelf building blocks in order to keep the total cost within acceptable limits.     

Manufacturability analysis a useful subset of systems engineering

The application of manufacturability analysis to the design of mechanical parts in electronic systems improves quality, performance and reliability. Typical interest areas include equipment enclosures, transducers and high-tech microwave modules. New performance levels are feasible due to improved surface quality, stability, reduction of seam widths or the use of sophisticated materials. The stepwise procedure points out attractive solutions for challenging airborne, maritime or space sensor platform environments. A thorough understanding of manufacturability judgement and knowledge about current milling, welding and coating processes is essential as well as the earliest application of the formulated principle     

Improving the productivity of complex electronic systems design byutilizing applied design methodologies

The design process of complex electronic systems consists of four traditional main stages, which are system design, electronic design, mechanical design, and design for manufacturing. Even today when many integrated computer aided design environments are in use for electronic systems design, we still seem to accept that the design process really has to follow this path of four individual design stages. It is common that we are dealing with data transfer problems between different types of CAE-applications. However, there is a possibility to avoid the disadvantages due to integration problems between the design stages if we decide to develop the design methodology itself instead of developing those independent software applications. One effective way to improve the productivity of complex electronic systems design is to tune the so-called systematic design approach by adding special aspects of electronic systems design into the questionnaires used for collecting the requirement lists for further mechanical design and DFM. Another important tool is the carefully made manufacturability analysis. The deep interaction of mechanical and electronic design, extended by manufacturability analysis can also lead to innovative solutions as presented previously by the author. In the article entitled “Manufacturability Analysis-A Useful Subset of Systems Engineering” we were able to show that the number of iteration cycles during the different design and manufacturing stages could be reduced by 50% compared to the conventional design methodology. In this paper, we illustrate additional tools to continue this promising development work     

Low-cost simulator for basic radar signals

Most modern radar simulators are costly and need cumbersome operations while used. Besides, they have many features not suitable for preliminary level. Basic training of radio monitoring personnel can be carried out with a simple and inexpensive system capable of producing both staggered and frequency hopping pulse radar signals with radiation pattern modulation. For operator convenience the system is programmed with basic programming language