Related papers: Fundamental Efficiency Limits for Small Metallic A…
Existing optimization methods are used to calculate the upper-bounds on radiation efficiency with and without the constraint on self-resonance. These bounds are used for the design and assessment of small electric-dipole-type antennas. We…
Small volume, finite conductivity and high frequencies are major imperatives in the design of communications infrastructure. The radiation efficiency $\eta_r$ impacts on the optimal gain, quality factor, and bandwidth. The current…
Performance limitations for implanted antennas, taking radiation efficiency as the metric, are presented. The performance limitations use a convex optimization procedure with the current density inside the implant acting as its degree of…
This paper presents radiation efficiency and gain bounds for microstrip patch antennas. The presented bounds are shown to be good predictors of antenna performance. Using the bounds, patch miniaturization techniques based on high…
Modern antenna design for communication systems revolves around two extremes: devices, where only a small region is dedicated to antenna design, and base stations, where design space is not shared with other components. Both imply different…
Considerable time is often spent optimizing antennas to meet specific design metrics. Rarely, however, are the resulting antenna designs compared to rigorous physical bounds on those metrics. Here we study the performance of optimized…
The fundamental limit for small antennas provides a guide to the effectiveness of designs. Gustafsson et al, Yaghjian et al, and Mohammadpour-Aghdam et al independently deduced a variation of the Chu-Harrington limit for planar antennas in…
Antenna miniaturization remains a critical technological challenge across frequency scales - from microwave RF links in phones and wearables to VLF for underwater-to-air communications and ionospheric probing. At deeply subwavelength scales…
Relative bounds on radiation efficiency are established for time-modulated antenna systems where radiation is generated by broadband conduction currents impressed using idealized non-radiating time-varying subsystems, such as those found in…
Operational bandwidth of resonant circuits is limited by the resonator's size, which is known as the Chu limit. This limit restricts miniaturization of antennas, as the antenna bandwidth is inversely proportional to its size. Here, we…
Far-field shaping of small antennas is a challenge and the realizations of non-dipole radiation of small to intermediate sized antennas are difficult. Here we examine the antenna bandwidth cost associated with such constraints, and in…
Fundamental bounds on antenna gain are found via convex optimization of the current density in a prescribed region. Various constraints are considered, including self-resonance and only partial control of the current distribution. Derived…
The rapidly advancing capabilities in nanophotonic design are enabling complex functionalities limited mainly by physical bounds. The efficiency of transmission is a major consideration, but its ultimate limit remains unknown for most…
Low cost methods of antenna production primarily aim to reduce the cost of metalization. This might lead to a reduction in conductivity. A systematic study on the impact of conductivity is presented. The efficiency, gain and bandwidth of…
We address the question of the optimal choice of loading material for antenna miniaturization. A new approach to identify the optimal loading material, dielectric or magnetic, is presented for resonant antennas. Instead of equivalent…
The low propagation loss of electromagnetic radiation below 1 MHz offers significant opportunities for low power, long range communication systems to meet growing demands for IoT applications. Especially in the very low frequency (VLF: 3-30…
Using ideas from Chu and Bode/Fano theories, we characterize the maximum achievable rate over the single-input single-output wireless communication channels under a restriction on the antenna size at the receiver. By employing…
Small form-factor, narrowband, and highly directive antennas are of critical importance in a variety of applications spanning wireless communications, remote sensing, Raman spectroscopy, and single photon emission enhancement. Surprisingly,…
Over the previous few years, the millimetre wave frequency range and sub-THz range have been received a lot of attention as they include unused frequency spectrum resources that are appropriate for providing a lot of applications such as…
Superdirective (supergain) antennas aim to produce a narrow main beam from radiators that are electrically small compared with the wavelength. Instead of enlarging the physical aperture, they rely on strongly coupled currents, near-field…