Antennegerichtheid

Antennegerichtheid is a Dutch term that translates to “antenna directivity” in English. It quantifies how strongly an antenna focuses radiated or received power in a particular direction compared to an isotropic radiator that radiates equally in all directions. Directivity is a dimensionless number, often expressed in decibels (dBi), and is defined by the ratio of the maximum radiation intensity to the average intensity over a sphere. The mathematical expression is D = 4π·Umax / Prad, where Umax is the maximum radiation intensity (W/sr) and Prad is the total radiated power (W).

High directivity allows an antenna to concentrate energy into a narrower beam, increasing signal strength over long distances while reducing interference from other directions. In applications such as satellite communications, radar, and microwave links, antennas with high directivity achieve longer link budgets and better resistance to multipath effects. However, greater directivity typically results in narrower beamwidths, demanding more precise pointing and alignment.

Directivity is closely related to antenna gain; the difference is that gain also accounts for loss mechanisms like ohmic loss and mismatch. Therefore, gain (G) equals directivity (D) multiplied by the power efficiency (η), often expressed as G = η·D. Because of this relationship, characterizing an antenna’s directivity provides insight into its theoretical performance potential before efficiency losses are considered.

Directivity can be determined experimentally using far‑field pattern measurements in anechoic chambers, or analytically via computational electromagnetic methods such as the method of moments or full‑wave solvers. Practical antenna types that exploit high directivity include Yagi‑Uda arrays, parabolic dish reflectors, and phased‑array panels. Each of these designs utilizes structural elements to shape the radiated field and achieve the desired directional characteristics.

In summary, antennegerichtheid is a fundamental performance metric for directional antennas, reflecting the concentration of radiated power into specific directions. It underpins the design of long‑range links, spatial filtering, and beamforming systems across many wireless technologies.