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This paper presents the architecture as well as the circuit implementation of a ZigBee transceiver using 2.45 GHz band, which is compliant with the physical layer of IEEE 802.15.4 standard. A prototypical system and chip has been designed using 0.18-μm CMOS process with core area of 0.16 mm 2 . The simulation results shows the packet error rate is less than 1% given E b /N 0 = 9 dB. The total power consumption is merely 271 μW at a 8.0 MHz system clock.Index Terms -WPAN, ZigBee, matched filter, direct sequence spread spectrum, wireless network

Inner product calculations are often required in digital neural computing. The critical path of the inner product of two binary vectors is the carry propagation delay generated from individual product terms. In this work, two novel architectures to arrange digital ratioed compressors are proposed to reduce the carry propagation delay in the critical path. Besides, the carry propagation delay estimation of these compressor building blocks is derived and compared. The theoretical analysis and Verilog simulation both indicate that one of the compressor building blocks we present here might offer a sub-optimal solution for the basic building blocks used in digital hardware realization of the inner product computation.

The wetting characteristics of the rubbed polymer thin films is studied by both statically and dynamically examining contact angle of a droplet of deionized water on the polymer surface. The rubbed polyimide thin films exhibit anisotropic surface wettability. In rubbing direction the rubbed polyimide shows higher hydrophobicity, whereas in the anti-rubbing direction, the polymer surface is more hydrophilic. The asymmetric polarity of the polymer surfaces owing to rubbing is considered to be responsible for the appearance of anisotropy in the contact angle hysteresis.