Patent ID: 6861971

Claim:
An apparatus operating as a transceiver or transponder particularly for synthetic aperture radar (SAR) systems, operating in a frequency band having a central frequency, the apparatus comprising: a receiver; a transmitter; wherein both the receiver and transmitter are thermally stable and made by microstrip technology; wherein the receiver and the transmitter are adapted to receive and to transmit, respectively, an electromagnetic wave provided with at least one linear polarisation; wherein the receiver is connected to the transmitter by amplifier means comprising an amplifier unit for each linear polarisation of the wave received by the receiver, each amplifier unit including at least two amplifier stages cascade-arranged along a single microstrip and interconnected to one another and to an input and to an output of the corresponding amplifier unit by means of coupling or matching stages, the output signal of each amplifier unit having substantially the same frequency as the input signal thereto; wherein the amplifier units have substantially the same gain, the gain being no lower than 25 dB; wherein the transponder is stable so that each linear polarisation of the transmitted electromagnetic wave has phase variations in time no higher than 20°; and electromagnetic decoupling means disposed between the transmitter and the receiver.