Observations of the amplitudes and Doppler shifts of received HF radio waves are compared with model predictions made using a two-dimensional ray-tracing program. The signals are propagated over a sub-auroral path, which is shown to lie along the latitudes of the mid-latitude trough at times of low geomagnetic activity. Generalizing the predictions to include a simple model of the trough in the...

Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. Series Title BO Satellite delivery BR Recording for production, archival an...

The problem of guided wave propagation in a wave guide with imperfectly reflecting boundaries arises in several applications, such as propagation in mine tunnels and in screened surface wave guides. In recent years, many studies have been carried out on the propagation characteristic of radio waves in tunnels in UHF band [1-2]. From the theoretical point of view, tunnels can be regarded as holl...

During polar-cap absorption events, which are caused by the incidence of energetic solar protons, the highlatitude ionospheric D region is extended down to relatively low altitudes. While the incoming proton fluxes may be monitored by satellite-borne detectors, and the resulting radiowave absorption with a ground-based riometer, the enhancement of electron density at a given altitude is less ea...

The development of heterodyne detection from the radiowave to the optical region of the electromagnetic spectrum is briefly reviewed. Attention is focused on the submillimetre/far-infrared region. A simple phenomenological model for the transition from electric-field to photon-absorption detection is developed. The relative detected power at doubleand sum-frequencies is multiplied by an attenua...

Accurate characterization of the electromagnetic wave scattering and propagation properties of the terrain surface is essential in optimizing the performance of wireless sensor networks (WSN) deployed for environmental monitoring and geophysical sensing applications. As the WSN nodes are positioned near or at the ground level, the conditions of the ground have a substantial effect on the radio ...