29 research outputs found
Feasibility of passive bistatic geosynchronous radar using comsat transmissions
Communication satellites in geosynchronous orbit are increasingly broadcasting digital signals with high bandwidth and high power. These signals are in principle well-suited to radar imaging and the study presented here is an initial feasibility study for a passive bistatic synthetic aperture radar using satellites in geosynchronous orbit (GEO). The persistent viewing possible from GEO could enable important new applications. The mission concept is outlined and studies of the available signal formats identify digital TV broadcasts in Ku-band as most suitable for radar imaging. The additional space hardware required is a dedicated receive channel, which could be implemented as a hosted payload at modest cost. Our findings so far suggest that the mission concept is feasible for coarse spatial resolution images and that it could therefore provide a low-cost technology demonstration of geosynchronous radar
Simultaneous data collection of small maritime targets using multistatic radar and forward scatter radar
Radar detection of small maritime targets is of great interest in the context of coastal and port security for prevention of activities such as smuggling and piracy. Multistatic radar and forward scatter radar offer detection advantages compared with conventional monostatic systems, such as advantageous multi-perspective target view for the former and target radar cross-section enhancement for the latter. In this study, experimental results are presented to characterise simultaneous measurements investigating the detection of a small inflatable boat by a multistatic radar and a forward scatter radar. These results are believed to be the first example of simultaneous experimental comparison of such systems
Full-wave analysis of fundamental modes of a multicoupled strip line with ferroelectric film
The properties of a multicoupled microstrip line (MSL) with a thin control ferroelectric layer have been analyzed in terms of a full-wave model based on the method of moments in spectral domain. The Q values for all fundamental modes and their contributions to MSL losses are determined. It is established that various fundamental modes in multicoupled MSLs are characterized by significantly different Q values. The proposed method has been applied to the analysis of characteristics of an MSL-based ferroelectric microwave phase shifter. The figure of merit F of the phase shifter has been calculated for each fundamental mode. The results of analysis lead to a conclusion that, by exciting a fixed mode characterized by the maximum Q value, it is possible to obtain an MSL-based phase shifter possessing the optimum F at a minimum necessary level of the control voltage. \ua9 2005 Pleiades Publishing, Inc