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The acoustic environment of the continental shelf slope waveguide is more complex than those with flat bottoms. For a long receiving array in this area, the amplitude and phase of the received signals will be distortional, leading an attenuation in the spatial correlation of the sound field and a degradation in the array gain of beamformers. This paper shows the performances of three beamformers:...
This paper presents the design of A S-band low noise amplifier (LNA), which is made up of two stages with Agilent's ATF-54143. The biasing circuit, input stage, middle stage and output stage matching circuits of the LNA are designed and simulated by the software Agilent ADS. At last, the designed circuit is fabricated and measured. It is showed that, from 2.15GHz to 2.65GHz, the gain is between 27...
An analytical and closed-form optimal solution expressed in elementary functions for superdirectivity of a circular sensor array is proposed in this paper. By utilizing the circulant property of the data covariance matrix for circular sensor arrays, such solutions are derived to accurately calculate the optimal beamforming vector, optimal beam pattern, corresponding directivity factor, and eigenbeams...
This paper proposes a three-stage broadband Doherty power amplifier with an extended efficiency range for TD-LTE application at 1.9–2.0GHZ. In this design, we use LDMOS devices with a power ratio of 1:1:1, The radial stubs are utilized in the dc bias network to increase the bandwidth. The power added efficiency of the proposed three-stage Doherty PA has been maintained 47% at an average output power...
This paper proposes a 450–470 MHz high efficiency three-stage Doherty power amplifier for IMT-Advanced system. The input matching and output matching are achieved by utilizing microstrip line and lumped-parameter components. Two 3dB couplers are utilized to carry out uneven input power dividing so as to omit the two quarter-wave lines which are usually located before the main amplifier and the second...
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