EHF appliques for VHF radios

For more than four years Hughes has been developing a family of covert radios for military applications. The EHF applique concept offers a straightforward means of obtaining covert communications while benefiting from the existing inventory of military radios. The nucleus of this work is an EHF applique unit which can translate a wide variety of lower band signals to the oxygen absorption band where excess path loss confines communication and intercept range. Experimentation and field test with two generations of covert applique units has yielded a reliable design with many potential applications across all services. For both generations of equipment, measured unit performance corresponds to prior theoretical calculations within 2 dB for all of the test scenarios described subsequently