Yu-Feng Ruan

Wide-band stacked double annular-ring dielectric resonator antenna at the end-fire mode operation

A novel wide-band stacked double annular-ring dielectric resonator antenna (DRA) is numerically investigated in this paper. At either layer, a larger annular-ring dielectric resonator is placed concentrically outside a smaller annular-ring one to form a stacked double annular-ring DRA. The antenna is operating at the end-fire mode. The effects of antenna parameters such as dielectric constant, probe length and air-gaps thickness are investigated. Compared to the obtained 18% bandwidth of the stacked annular-ring DRA, the proposed stacked double annular-ring DRA can offer an impedance bandwidth of /spl sim/42% for the return loss below -10 dB. The radiation patterns are stable in the passband.

A study on the performance of space-time coding UWB-impulse radio system in IEEE 802.15 multipath channels

In this paper, the performance of the space-time coding ultra wideband impulse radio system in a typical IEEE 802.15 multipath channel is studied. In the proposed scheme, only two transmit antennas and one receiver antenna are employed and no channel information feedback is needed. We investigate how the temporal and spatial diversity influence the multiple access performance and how the space-time coding technique is used to mitigate the multiple access interference (MAI) and the inter-symbol interference (ISI) thereby improves the bit error rate performance of the ultra wideband impulse radio system. Numerical results show that the space-time coding technique is an efficient means to improve the performance of ultra wideband impulse radio system under IEEE 802.15 multipath environment in both one single user and multi users environment.

Optimal UWB Waveform Design for Antenna Dispersion Compensation

A new pulse design method for Ultra-wideband (UWB) radios is proposed. By precisely formulating the effective isotropic radiated power, the proposed method can properly pre-compensate the antenna dispersion effects. Compared to the existing waveform design methods, the proposed method can provide much more efficient utilization of the FCC assigned spectrum.

A Compact Wideband Printed Wire Antenna for Wireless Communications

This paper presents a compact dual-band printed-circuit-board wire antenna for wireless communications applications. The proposed wire antenna in F-shape with a shorted parasitic element can offer two separate impedance bandwidth of about 0.8 GHz (2.3 GHz~3.1 GHz) and 2 GHz (4.1 GHz~6.1 GHz) for a return loss less than -10 dB. Moreover, the antenna remains compact in size, making it a good candidate for Bluetooth and wireless local area network (WLAN) operation in the 2.4 GHz band and 5.2/5.8 GHz band. Measured results, including return loss and Smith chart, are presented