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Development of 4×4 annular ring array based digital transceivers for long distance UWB wireless communications

This paper presents design and realization of subcomponents for a prototype 4x4 ultra wide band (UWB) communication device. The sub-components are four quadrature phase shift keying (QPSK) modulated direct digital transceivers using QPSK modulation scheme operating on the lowest channel of multi-band orthogonal frequency division multiplexing OFDM (MB-OFDM) approach over 3.168- 3.696 GHz. InGaP/GaAs HBT based integrated circuit (IC) realization of the receiver consist of a low noise amplifier (LNA) with a stable gain of 26 dB and a noise figure of 1.5 dB, a Gilbert-cell mixer (GCM) with a conversion loss of 4 dB, and a poly-phase circuit to provide four 0, plusmn90 and 180 degrees phase shifted signals for the GCM. A similar up-conversion unit is considered where the LNA may functions as a gain block. The power budget and dynamic range requirements for a radio link distance up to 100m are analyzed in various faded environments to provide a minimum bit error rate of 10"'. A 4x4 circularly polarized (CP) antenna array with a directivity gain of 20dBi is developed to compensate for the link power loss.