This paper discusses the integration of array antennas in chip packages for highly integrated 60-GHz radios. First, we evaluate fixed-beam array antennas, showing that most of them suffer from feed network complexity and require sophisticated process techniques to achieve enhanced performance. We describe the grid array antenna and show that is a good choice for fixed-beam array antenna applications due to its easy feed network design and manufacture. Then, we examine switched-beam array antennas using the Rotman lens or Butter matrix, illustrating that they allow scanning only in one plane and some miss a link even in the boresight direction. Nevertheless, a switched-beam array antenna uses a conceptually simple switch circuit to select the best signal path and may be a cost-effective approach to implementing steerable antennas in the 60-GHz band. Finally, we describe adaptive beam or phased array antennas and highlight the challenges and practical realizations of phased array antennas in both ceramic and organic chip packages for single-chip 60-GHz radios.

As a potential future technology, impulse radio is a promising new reliable data transmission method for time-sensitive applications. However, owing to the complex nature of ultra-wideband (UWB) channels used in practice, there are many design problems that remain to be resolved. This study looks into some UWB channels classified as waveform distortion for which the authors present an implementation-oriented analysis to investigate the performance of impulse radio systems using antennas for a special class of deterministic multipath channels. This study analyses the waveform distortion along signal path to identify the effect of non-idealities in the system and evaluates overall performance of system in terms of bit error ratio observing the waveforms received at the correlator. Through simulation results practical aspects of the impulse-radio transceivers are discussed. From some of the results, the authors provide an antenna selection strategy for some propagation environments.

We propose an imperfect waveguide model to represent empty curved tunnels. We use the field configuration in an optical dielectric guide together with the surface impedance boundary condition for the walls to simplify the complexity of derivation of the propagation modal equations. The curvature of the tunnels is assumed to be gentle. Our results show that increased propagation loss is almost linearly proportional to frequency and inversely proportional to the radius of curvature.

This paper presents the measured local mean and variability of UHF mobile radio signals in tunnel environments. The results show that the fast fading mainly depends upon the tunnel dimensions and frequency and the fast fading of the received signal fits well with the Rayleigh distribution. As far as the local mean component of received signal is concerned, a signal strength distance factor has been derived to vary from 1.4 to 1.7, which is different from the value 1, suggested by the current deterministic model.

The paper presents the measured time delay characteristics of 2.4 GHz band radio propagation channels in room environments. The measurements were made using the swept frequency technique with a different calibration method. The analysis of the average measured power-delay profiles reveals that the rms delay spread is less than 50 ns when the receive antenna (RA) is in the lit region and can be as large as 217 ns when the RA is in the shadow region. A simple wide band channel model is also recommended for the in-room environments.

12 GHz band wave propagation measurements in rooms of different uses have been performed. Analysis to the measured data reveals that the in-room signal attenuation followed the simple d to power n law where n ranges from 1.5 to 2.3, and the in-room signal distribution adheres to the Rician distribution.>

Measurements of the frequency characteristics of the penetration loss over the frequency range of 900 MHz to 18 GHz have been made for typical indoor walls. Measured results show the indoor penetration loss increases with frequency for reinforced concrete wall. However, this general trend does not remain true for plasterboard walls.>