Achievable Rate With Antenna Size Constraint: Shannon Meets Chu and Bode

Using ideas from Chu and Bode/Fano theories, we characterize the maximum achievable rate over single-input single-output wireless communication channels under a restriction on antenna size at receiver. By employing circuit-theoretic multiport models for radio systems, derive information-theoretic limits of compact antennas. We first describe an equivalent Chu’s circuit physical realizability conditions its reflection coefficient. Such design allows us to subsequently compute given receive thereby providing bound system performance that compare standard size-unconstrained Shannon capacity. also determine effective signal-to-noise ratio (SNR) which strongly depends experiences apparent finite-size degradation where only fraction capacity can be achieved. further optimal signaling bandwidth shows impedance matching is essential in both narrowband broadband scenarios. examine presence interference showing constraint immaterial interference-limited Finally, our numerical results derived as function SNR reveal new insights physically consistent systems.