Sang-min Han

Low power UWB RF transceiver for wireless headset

In this paper, the UWB RF transceiver architecture based on a direct chaotic communication system is introduced for wireless headset applications. The direct chaotic communication technology can realize excellent low data rate UWB communication. The low power RF transceiver with chaotic UWB signal of 3 GHz /spl sim/ 5 GHz is implemented for MP3 audio transmission. This simply configured system prototype performs non-coherent detection without up/down mixers. The system is expected E/sub b//N/sub 0/ of 18 dB for PER /spl les/ 10/sup -2/ at 32 bytes length of PSDU, and power consumption of 20 mW in case of 0.13 micron CMOS RFIC fabrication.

Low-Rate Chaotic UWB Transceiver System Based on IEEE 802.15.4a

The chaotic UWB communication system based on IEEE 802.15.4a is proposed for wireless headset applications. A compact architecture can be implemented by using a chaotic UWB signal and a non-coherent detection scheme. The chaotic UWB generator is designed with the BW of 3.1 to 5.1 GHz, and a baseband process is realized on an FPGA including an adaptive decision and a channel code for non-source coded data stream. The system performance is evaluated by transmitting MP3 audio/voice and measuring PERs at 32 byte length of a PSDU for the system sensitivity and the interferer compatibility. The proposed system can be an excellent candidate for short-range connectivity services, as well as an inexpensive system with good capability for narrow-band interferences

Chaotic UWB Communication System for Low-Rate Wireless Connectivity Applications

A chaotic UWB communication system based on IEEE 802.15.4a is proposed for wireless connectivity applications. A compact and simple architecture is implemented by using a chaotic UWB signal and a non-coherent detection scheme. The chaotic UWB signal has noise-like characteristics in time and frequency domains and naturally wide spectrum within a limited bandwidth. The chaotic UWB signal generator is designed on two methods with the bandwidth of 3.1 to 5.1 GHz, and a baseband process is realized on an FPGA including an adaptive decision and a channel code for non-source coded data stream. The system performance is evaluated by transmitting MP3 audio/voice with 32-byte length PSDUs and measuring PERs for assessing the system sensitivity and the interferer compatibility. The proposed system can be an excellent candidate for short-range connectivity services, as well as an inexpensive system with good capability for narrow-band interferences.

Chaotic UWB transceiver with tunable chaotic signal generation in CMOS 0.18um technology

The chaotic UWB RF transceiver system is designed in CMOS 0.18 mum technology with flexible chaotic signal generation. Although the chaotic UWB technology is expected as a promising solution for near-range connectivity services, it has a limitation for commercial applications due to a fixed-band chaotic signal generator. In this paper, the noble flexible chaotic signal generator with adjustable frequency range and bandwidth is proposed. It has a simple architecture configuring of a noise generator, an FM modulator, and control circuits. The center frequency of the chaotic signal can be controlled from 3.5 to 4.5 GHz, while its bandwidth is adjusted from 70 to 620 MHz. The key block of the chaotic UWB RF transceiver is fabricated in CMOS 0.18 mum technology. The performance of the chaotic transceiver system is evaluated for transmission of digital data of 15 Mbps and non-coherent adaptive detection scheme. The proposed system can be an excellent candidate for short-range connectivity services, as well as inexpensive systems.

Higher phase-tunable phase shifters using DGS termination loads

New phase shifters with higher phase shift values are presented using defected ground structures (DGSs). The varactor diodes are mounted on DGSs of termination loads to control the large phase variation of the DGS at resonance. Two types of phase shifters are implemented with a branch-line and a coupled line hybrid. The experimental results of the proposed phase shifters show 135% and 221% increases in maximum phase shifts, respectively, compared with those of conventional ones.