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Radio and Electronic Engineer

Issue 4 • Date 1967

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Displaying Results 1 - 7 of 7
  • Computers in britain

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    Freely Available from IEEE
  • Broadbanding of concentric planar ring arrays by space tapering

    Page(s): 211 - 222
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1108 KB)  

    The paper discusses the application of concentric ring arrays as a new approach to space tapering for planar arrays. It describes the design of an array of non-uniformly spaced concentric rings of non-uniform density containing discrete elements. The array can be operated over a large frequency range and wide scan-angles. The ring array was designed to simulate the performance of a Taylor-weighted circular aperture. An array having a diameter of 34 wavelengths was designed with ten concentric rings containing a total of 759 elements and a thinning factor of 0.21. This array has a side-lobe level of ¿20 dB or better over a range of sin ¿ up to 2.5 at mid-band. Taking a dielectric filled square-guide as the radiating element, the mutual coupling was calculated. The element spacing is 0.498 ¿mid for the innermost and 1028 ¿mid for the outermost ring. The mutual coupling does not produce any appreciable deleterious effect on the array-factor. For the scan angle of ¿0 = 60° and ¿0 = 0°, the array has a side-lobe level better than ¿20 dB for a frequency range of 0.75 ¿mid to 1.25 ¿mid. View full abstract»

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  • Field-effect studies on indium antimonide films

    Page(s): 223 - 228
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (901 KB)  

    Field effect studies have been carried out on thin film InSb inert insulator solid-solid interfaces. The films were prepared by the protected recrystallization method, namely vacuum evaporation and subsequent annealing of the resulting insulator-semiconductor-insulator sandwiches. The high annealing temperatures permissible without danger of reevaporation of the more volatile component gave films with high mobility of approximately 103¿104cm2/V-s and relatively low carrier concentrations of approximately 1016¿1017/cm3. The good bonding of the insulator on to an inherently clean semiconductor surface resulted in a low fast surface state density of approximately 5 × 1011/cm2, which would permit the use of these films for field effect transistor applications. Thin films are very well suited for field effect investigations. Surface Hall effect and surface conductivity against surface potential gave the trapped and mobile charge density with the relevant Hall and field effect mobility directly. A model of fast surface states based on these results is proposed. View full abstract»

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  • The preparation and application of tantalum thin film passive components

    Page(s): 229 - 240
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    The paper commences with a comparison of thin film and diffused passive components, then describes the methods of fabricating resistors and capacitors by using sputtered tantalum and also inductors using nichrome/gold. The reasons for choosing tantalum as the resistor material and sputtering as the deposition method are discussed. The work described in the paper has concentrated on making resistor and capacitor dimensions as small as possible without seriously affecting their properties. Resistors less than 0.001 in wide and capacitors with 1 pF per 0.001 in square of electrode area can be made, so that small, and thus economical, circuits can be realized. The performance of thin film resistors, capacitors and inductors is given and one section is devoted to the behaviour of resistors when dissipating high powers (over 1 kW/in2) at elevated temperatures. Methods of bringing together active devices and the thin film components are considered, emphasizing that since the active and passive devices can be made small, then the method of combining the two should take advantage of these small dimensions. The two methods discussed are the `flip-chip¿ techniques for adding active devices to a substrate with thin film components and the use of an active substrate, in which the thin film components are fabricated on oxidized silicon which contains the active devices. The use of `flip-chip¿ techniques for mounting integrated circuits on thin film interconnection patterns is also discussed. Examples are given which demonstrate how thin film resistors, capacitors and inductors with active or passive substrates can be used in electronic circuits. View full abstract»

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  • The development of a pay-television system and equipment

    Page(s): 241 - 256
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    The system described applies to wired-broadcasting networks of the multi-pair variety. The pay-television user establishes credit by the insertion of one or more coins into a special subscriber's unit. The established credit will be consumed at a faster rate for an expensive programme, and vice versa. On the other hand, the subscriber can at any time switch off, and preserve the remaining credit for some future occasion. If the credit is exhausted, the unit switches off, and no pay-television programme can be received until more money is inserted. Means are provided in the central station from which the pay-television programmes emanate and from which the price is controlled to display numerically and to print out minute by minute how much money has been collected from viewing subscribers since the start of a particular programme. This is achieved by digital techniques combined with data transmission, and it constitutes a complete, automatic and instant accountancy system. View full abstract»

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  • An H-plane high-power TEM ferrite junction circulator

    Page(s): 257 - 262
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    In this paper a new junction circulator is described which consists of a composite junction having a beryllia disk sandwiched between two oversized garnet disks on each side of the TEM lines. In this way the r.f. power is evenly divided among four thin garnet disks. This approach results in a very large thermal capacity. A general characterization of the junction in terms of the experimental admittance function is also given. This approach is used to make the junction one of the resonators of a two-section filter. The final circulator was tested at 150 kW peak power and 2.5 kW average power at 1300 MHz. View full abstract»

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  • Low frequency sound sources: statement of problem and some possible solutions

    Page(s): 263 - 272
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    The main stumbling block in a project to measure the backscattering cross-section (target strength) of commercial fish at frequencies in the band 300 Hz to 3000 Hz has been that of providing a suitable sound source. The spectrum level requirement of this source is + 70 dB relative to 1 ¿bar (0.1 N/m2) at 1 m per Hz across the band, or about 100 W peak power during a 10 ms pulse at any frequency. The general problem of radiating this power level into water at these frequencies is considered. Several sources employing various principles of transduction including sparkers, boomers, explosives, hydroacoustic, electrodynamic, piezoelectric and magnetostrictive sources, are considered in terms of a common parameter¿the maximum output spectrum level¿as well as efficiency. View full abstract»

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