Hon Tat Hui

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can be roughly estimated in the direction of = cos 01 (=k0), where is the elevation angle from the microstrip, and k 0 is the free space wavenumber. The propagation constants can be derived by solving the spectral domain integral equations with appropriate integral contour of the inverse Fourier transform and the moment method numerical technique [10]. The(More)
—Random beamforming (RBF) is a practically favourable transmission scheme for multiuser multi-antenna downlink systems since it requires only partial channel state information (CSI) at the transmitter. Under the conventional single-cell setup, RBF is known to achieve the optimal sum-capacity scaling law as the number of users goes to infinity, thanks to the(More)
—A new method for calculation of the mutual impedance is introduced for the compensation of mutual coupling effect in a dipole antenna array employed for direction finding. This method uses an estimated current distribution and a different method for the calculation of the open-circuit voltage. It is shown that the new method can significantly improve the(More)
The random beamforming (RBF) scheme, jointly applied with multiuser diversity based scheduling, is able to achieve virtually interference-free downlink transmissions with only partial channel state information (CSI) available at the transmitter. However, the impact of receive spatial diversity on the rate performance of RBF is not fully characterized yet(More)
A new concept of using a stacked phased coil array to increase the signal-to-circuit noise ratio (SCNR) in magnetic resonance imaging (MRI) is introduced. Unlike conventional phased coil arrays, the proposed stacked phased coil array is constructed by stacking the coil elements closely together in the vertical direction. Through a proper combination of the(More)
A new method is introduced to increase the signal-to-noise ratio (SNR) in low-field magnetic resonance imaging (MRI) systems by using a vertically stacked phased coil array. It is shown theoretically that the SNR is increased with the square root of the number of coils in the array if the array signals are properly combined to remove the mutual coupling(More)