Related papers: Fundamental Efficiency Limits for Small Metallic A…
We experimentally demonstrate a Purcell effect-based design technique for improved impedance matching, and thus enhanced radiation efficiency from a small microwave emitter. Using an iterative process centred on comparing the phase of the…
MIMO capacity with a joint total and per-antenna average power constraint is considered in this work. The problem arises when, besides having a limited available power at the transmitter, also the individual antennas cannot radiate power…
In this paper we study microstrip antenna miniaturization using partial filling of the antenna volume with dielectric materials. An analytical expression is derived for the quality factor of an antenna loaded with a combination of two…
The stringent spatial constraints and the demand for high antenna efficiency in modern wireless earphones present significant design challenges. To address these issues, this paper presents and thoroughly investigates a novel earphone…
Conventional mechanical antennas provide a strategy in long-wave communication with a surprisingly compact size below 1/1,000 of the wavelength. However, the narrow bandwidth and weak field intensity seriously hamper its practical…
Hannan Limitation successfully links the directivity characteristics of 2D arrays with the aperture gain limit, providing the radiation efficiency upper limit for large 2D planar antenna arrays. This demonstrates the inevitable radiation…
Hyperbolic metamaterials were initially proposed in optics to boost radiation efficiencies of quantum emitters. Adopting this concept for antenna design can allow approaching long-standing challenges in radio physics. For example, impedance…
The Chu circuit model provides the basis for analyzing the minimum radiation quality factor, Q, of a given spherical mode. However, examples of electrically large spherical radiators readily demonstrate that this Q limit has limitations in…
Design of antennas for modern applications is a challenging task that combines cognition-driven development of topology intertwined with tuning of its parameters using rigorous numerical optimization. However, the process can be streamlined…
In this work, a parametric up-converter amplifier is introduced as a wideband impedance matching network for receiving electrically small antennas. Chu's limit restricts the minimum Q-factor of unloaded small antennas; however, the…
Implantable bioelectronics often relies on an RF-wireless link for communication and/or remote powering. Propagation through biological media is very lossy, and previous work has shown that these losses can be separated into three parts:…
Massive MIMO systems promise high data rates by employing large number of antennas, which also increases the power usage of the system as a consequence. This creates an optimization problem which specifies how many antennas the system…
The main goal of this work is to theoretically investigate the behavior of an electrically small antenna enclosed in a concentric sphere. The Greens function analysis is applied to characterize the input impedance of a concentric resonator…
The problem of finding the optimal current distribution supported by small radiators yielding the minimum quality (Q) factor is a fundamental problem in electromagnetism. Q factor bounds constrain the maximum operational bandwidth of…
A three-dimensional model of a novel plasma based electrically small antenna is developed for investigating the gas properties and antenna parameters under a low pressure, low plasma temperature environment. The antenna exhibits dipole…
To overcome the physical limitations of electrically small antennas, strain-mediated magnetoelectric antennas have been studied experimentally and theoretically. However, current closed-form analytical models include solely one-dimensional…
Terahertz (THz) metalens antennas with compact planar structures have demonstrated significant potential in enhancing gain and aperture efficiency through beam convergence. However, research on THz wireless communication systems utilizing…
Electric and magnetic currents are essential to describe electromagnetic stored energy, as well as the associated quantities of antenna Q and the partial directivity to antenna Q-ratio, D/Q, for general structures. The upper bound of…
A conceptual method to realize an impedance-matched electrically small antenna is discussed, using a transmission line modulated only in time. The time-periodic space-uniform modulation of a distributed shunt array of varcapacitors excites…
Slot antennas are very popular microwave antennas and slotted wave guides are used for high frequency radar systems. A thin slot in an infinite ground plane is the complement to a dipole in free space. This was described by H.G. Booker [2]…