The receiving antenna array (rectenna), on the ground is characterized by immediate rectification from RF to DC. A typical configuration is shown in Figure 3. Individual dipole antennas are used as the receiving element and since rectification takes place immediately, DC power is collected from each element and fed into parallel and series strings to build up the voltage and current levels. Figure 4 illustrates the overall microwave PTAR concept showing subsystem inter-relationships in both the transmit and receive arrays. Since the reference concept was developed, new interest has been generated in utilizing solid state power amplifiers, primarily because of the anticipated increase in reliability over the klystron. As shown in Figure 1, these can be used in either the separate antenna approach or in the optical reflector/ sandwich approach. . To the depth studied it appears that cost per kilowatt may be somewhat higher than the reference system, although as cost estimates have been refined, the costs have trended toward convergence. As a result of the evaluations to date in the Concept Development and Evaluation Program, there are certain conclusions which can be reached on the Microwave PTAR System. One overall conclusion is that the transfer of gigawatt power levels between two points using microwaves is feasible. Other conclusions of a more detailed nature were presented at the system workshop previously mentioned. Also identified were certain remaining issues which must be addressed if the system concepts are to be more fully understood. Results of the workshop will be presented in another session paper. Other session papers will present results of the SPS program evaluations on the Microwave PTAR System.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==