Abstract: A phased-array antenna is provided with a dummy antenna element and a dummy transmit/receive module for testing the other transmit/receive modules by transmitting test signals to, or receiving test signals from, the other antenna elements in the array. Test signals are transmitted in a test mode that alternates with normal-mode operation. Receive power level and/or phase can be checked. The transmit/receive modules in the array are simplified in structure and improved in reliability due to the elimination of special receive check circuits. Antenna accuracy can also be improved by adjusting the phase shifters in the transmit/receive modules to compensate for variations in transmission phase.

Abstract: Two identical variable voltage source include respective capacitors serially interconnected across a series combination of a capacitive load and a fixed voltage source. Each variable source further includes a commutation reactor having two windings electromagnetically coupled and connected to each other, and two thyristors connected across the capacitor through one of the reactor windings to invert a voltage across the capacitor from its positive to its negative polarity and vice versa respectively. Either one of two low impedance DC sources charges the capacitor through a mating thyristor and the other reactor winding.

Abstract: A combined converter and inverter circuit is disclosed. A transformer has a primary winding connected across a DC source through two parallel switching thyristors with respective diodes and a secondary winding connected across two AC terminals through a filter. Two series thyristors with diodes are connected across the primary winding to be able to form closed current loops. In the DC-to-AC conversion the switching thyristors invert DC power to produce AC power including a reactive component flowing through the closed loop. In the AC-to-DC conversion the closed current loop causes the storage of electric power on the filter and the diodes across the switching thyristors rectify the stored power for charging the DC source.