Ultra-wideband Chip Research Articles

A Novel Polarization and DOA Reliable Auto-Tracking Antenna System

In this study, a novel compact auto-tracking antenna system was developed to ensure the high reliability of practical applications. The system consisted of three antennas (two anchor antennas and a tag antenna), three ultra-wide band (UWB) chips, and one compact turntable. On the anchor side, two highly linearly polarized antennas with a short baseline were installed on an auto-control turntable. Two UWB chips were integrated with the two anchor antennas to extract the phase and amplitude information of the receiving signal. On the tag side, a wide-beam circularly polarized antenna with a UWB chip was installed to mitigate the effect of the tag’s pose on the phase measurement. Using a correlation matching algorithm based on the phase difference of arrival, high tracking reliability with a 90% success rate was achieved for all practical direction-of-arrivals and various axial rotating angles of the tag over the maximum radiation deflection angles between –90° and 135°. The operation distance of a demo self-balanced two-wheeled vehicle was 20 m.

A Compact UWB Bandpass Chip Filter on a GaAs Substrate with Modified Chebyshev Structure

Ultra-Wideband (UWB) systems are widely used in low-power, high-speed, high-security short-range wireless communication systems throughout digital homes and offices. In the RF front-end of a UWB system, bandpass filters (BPFs) are used to put through the passband signals and reject the stopband signals. Most UWB BPFs are designed with dielectric materials on circuit boards or LTCC technology. In this paper, a very compact fully integrated UWB chip filter is proposed and designed on a GaAs substrate with nitride as dielectric layers to meet the small size requirement of portable devices for next-generation UWB applications. The filter is constructed with a modified Chebyshev structure. The final filter circuit contains only four inductors instead of six for the conventional Chebyshev filter, which makes the chip more compact and cost effective. The filter is designed and fabricated on a 0.25 μm GaAs pHEMT technology with a chip size of only 0.73 mm × 0.51 mm including the chip edge and scribe line area, while the filter core area is only 0.61 mm × 0.39 mm, including bonding PADs. The measurement results illustrated that the proposed BPF shows a passband covering the frequency range of 3.1–9.0 GHz, the minimum passband insertion loss is only 1.5 dB, the stopband rejection is better than −30 dB throughout frequencies below 2 GHz and above 12 GHz, S11 is less than −16 dB, and S22 is better than −11 dB during the whole passband range. It demonstrated that the proposed filter can be considered as one of the most compact UWB filters.