US Government As Represented by the Secretary of the Army

Jihun Choi

Fikadu T Dagefu

Kamal Sarabandi

Brian M Sadler

Justin S Kong

We disclose a novel methodology for wireless networks that optimizes the transmission probability, transmit power at an agent, and the reflection matrix of an IRS for covert RF communications. Key features include: (1) An exact closed-form expression for the expected detection error probability (DEP) at an adversary is provided considering the transmission probability at the agent; and (2) a novel method to optimize the transmission probability, transmit power at the agent and the reflection matrix of the IRS with the goal of maximizing the achievable rate at a client while ensuring a covertness constraint is developed. More specifically, the method may require only one-dimensional line search schemes, achieves near-optimal performance, and exhibits enhanced achievable data rate when compared to the conventional technique without the transmission probability optimization.

Covert communication technique for intelligent reflecting surface assisted wireless networks

An active matching network for impedance matching to a miniature antenna, comprising a cross-coupled transistor pair, where each transistor has an emitter, base and collector, the emitter of a first transistor forms an input terminal, the emitter of a second transistor forms on output terminal, the collector of the first transistor coupled to the base of the second transistor, the collector of the second transistor coupled to the base of the first transistor, and a matching circuit coupled between the collectors of the first and second transistors. The matching network is configured to match an impendence near resonance of the high Q miniature antenna to an input impedance using a complex negative impedance comprising resistance, inductance and capacitance.

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Silver Spring, MD, United States of America

Jihun Choi