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This paper proposes a transmitarray antenna consisting of a four-layer FSS (Frequency Selective Surface) array and a horn antenna. From reciprocal theorem, the designed transmitarray system can be used to receive satellite signals using the horn antenna. The transmitarray system is operated in Ku-band satellite downlink band, which ranges from 10.7 GHz to 12.75 GHz. The four-layer FSS are printed...
A broadband probe-fed array antenna for Ku-band applications covering 10.7–12.75 GHz, a bandwidth of 2.05 GHz, is proposed. The array antenna adopted 4×4 configuration with a parallel branch feeding network to set up required equal current magnitudes and phases. The antenna element in the array utilizes a vertical pillar to reduce the surface wave loss and increase operation bandwidth. The bandwidth...
The derivative superposition (DS) technique is used to cancel the third-order intermodulation distortion (IMD) produced in a downconverter mixer. By providing separate bias currents to the mixer core and the distortion-cancelling circuitry, the IMD is reduced but the conversion gain remains nearly the same in the distortion-cancelling mixer compared to the baseline mixer without linearization. Measurements...
A 2–10 GHz Gilbert-type mixer is reported in which the gate widths of the transistors in the RF stage are reconfigurable. The change in the total gate-width of the RF devices ultimately results in a variable conversion gain for the mixer. Measurements show that the conversion gain can vary from a maximum of 24 dB to a minimum of 9 dB. The IP1dB is −19 dBm at the highest conversion gain setting and...
A single-sideband upconverter mixer with sideband selection capability is presented. Sideband selection is accomplished by inverting the polarity of either the I or Q differential IF signals into the upconverter by means of a switch network. The mixer operates at an LO frequency of 5 GHz and an IF of 100 MHz, and thus it produces an upper sideband at 5.1 GHz and a lower sideband at 4.9 GHz. Experimental...
Difficulties in collection of electric toll have affected the normal operation and development of power supply bureau seriously. So the arrear problem of power customer has become one of the focus questions that power supply bureau pays attention to. In this paper, based on information entropy theory and on data mining technology, we have proposed a new data mining approach. This approach can measure...
This paper is concerned with the problem of adaptive fuzzy control for nonlinear systems with an unknown time delay and unknown control gain. Using an appropriate Lyapunov-Krasovskii functional, uncertainty of the unknown time delay is compensated for, and then the Fuzzy logic system in Mamdani type is utilized to approximate the unknown nonlinear function. By the use of Lyapunov stability theorem,...
Recently, Lee et al. proposed a remote authentication model of information appliances (RAMIA). Unfortunately, RAMIA has a fatal error that opens the entire home network of information appliances to hackers. In this paper, we propose a new secure remote control model for information appliances (SRCMIA) to fix this error. Besides, our model can also achieve both message authentication and one-time secret...
Mutual coupling effects on the performance of linear antenna arrays with corporate feed are investigated in this paper. Formulas of the reflection coefficients for arrays fed through Y-branch power dividers are derived. For a two-element array, it is shown that the reflection coefficient at the input of the array is approximately the linear superposition of scattering coefficients S11 and S12 of the...
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