NOVELTY - The system (200) has a transmit module (212) transmitting radio frequency (RF) energy of selected frequency bandwidth e.g. X band. A waste heat harvester e.g. thermophotovoltaic cells, includes thermophotovoltaic (TPV) material to receive waste heat from the transmit module and to convert the waste heat to electricity. The transmit module comprises a monolithic microwave integrated circuit (MMIC). The MMIC comprises a high-temperature semiconductor. A set of antenna elements includes a combined aperture area. A photonic crystal is placed between the transmit module and the TPV.    USE - Radar transmit-receive MMIC array antenna system for providing power aperture linearization for airborne applications in radar systems. Uses include but are not limited to airship applications, ground applications, water craft applications and space applications.    ADVANTAGE - The systems prevents power aperture curve from reversing downward trend at minimum value as aperture increases, thus allowing indefinite increase in aperture and decrease in power, and hence improving the radar of a large array. The system includes a transmitter with high-temperature solid-state power amplifier for operation at high temperatures, thus reducing or eliminating need for thermal heat spreaders or heat sinks. The system increases aperture size and corresponding reduction in aperture power, thus facilitating reduction in system mass. The system performs thermal separation so as to allow the receiver to be actively cooled, thus reducing noise and power levels. The TPV adds negligible weight and minor cost, while reducing net transmit power consumption. The system increases efficiency of radar transmit and TR modules. The system realizes more effective heat rejection at lower weight, reduces receiver noise and noise bandwidth and increases an aperture of an antenna without leading to increase in power requirements. The system cools a signal logic block of the receiver portion of the module so as to improve signal to noise ratio (SNR) of the module. The system improves efficiency of a solar cell.    DETAILED DESCRIPTION - The TPV comprises quantum dot (QD)-based material. The high-temperature semiconductor comprises silicon carbide (SiC), aluminum nitride (A1N), gallium nitride (GaN) and indium nitride (InN). The photonic crystal comprises a stacked array of tungsten elements. An INDEPENDENT CLAIM is also included for a solar cell comprising a photodiode.    DESCRIPTION OF DRAWING(S) - The drawing shows block diagram of a radar transmit-receive MMIC array antenna system.    Radar transmit-receive MMIC array antenna system (200)    Transmit module (212)    Main system bus (216)    Power connection (218)    Receive module (232)