Category - 1. Ideal Antennas

Learning Antennas Through Simulation: A Hands-On Guide with AN-SOF By TONY GOLDEN RF Engineer & Physics Ph.D. | CEO & Founder | Golden Engineering LLC This content is for subscribers only If you have already subscribed, please log in to access the book. 🔐 Log In After logging in, please refresh any open page to […]

Maxwell’s Equations: The Foundation of Electromagnetism Before A Treatise on Electricity and Magnetism (1873), the monumental two-volume work of James Clerk Maxwell (Fig. 1), the fields of optics, electricity, and magnetism were largely regarded as independent and conceptually isolated from one another. As often happens in the history of science, however, the unification of these […]

Spherical Coordinates and Their Role in Electromagnetic Waves Since real-world antennas radiate spherical waves, at least beyond a certain distance from the antenna, spherical coordinates will be frequently used in our analysis. Cylindrical coordinates will also be required later, particularly when studying cylindrical linear antennas, but those will be introduced in their respective chapter. For […]

The Hairy Ball Theorem and Isotropic Radiation Perfectly isotropic electromagnetic radiators in free space cannot exist. This limitation arises because the radiated fields are tangential to the spherical wavefronts and must necessarily vanish at least at a pair of points on the sphere. Consequently, if we observe the field intensities sufficiently far from a point […]

Heinrich Hertz and the Hertz Potential Heinrich Rudolf Hertz (1857–1894) was a German physicist whose pioneering experiments provided the first direct evidence of electromagnetic waves, as predicted by James Clerk Maxwell’s equations. In 1887, Hertz generated and detected radio waves in the laboratory, demonstrating that they exhibited the same properties of reflection, refraction, polarization, and […]

The Hertzian Dipole as an Idealization In deriving the field expressions for the Hertzian dipole, we treat it as an infinitesimally short filament of current. This means its length, $dl$, is vanishingly small compared to the wavelength, $\lambda$ (i.e., $dl \ll \lambda$). A key assumption of this model is that the current, $I$, remains uniform […]

Current Distribution To recap the path followed so far: we began by examining the elementary Hertzian dipole, which has a uniform current distribution and infinitesimal length. We derived its general field expressions, identified the far-field components, and introduced feed-point parameters such as radiation resistance, loss resistance, input reactance, and efficiency. Next, we defined key radiation […]

Current Distribution Along a Thin Dipole In the previous section, we examined the half-wave dipole in detail, as it is both widely used in practice and one of the fundamental antennas that every engineer should understand. For simplicity, we assumed the dipole was infinitely thin, so its radiation parameters (radiation resistance and directivity) do not […]

Introduction to Image Theory In many practical antenna systems, the antenna does not radiate in free space but operates in the presence of a conductive surface, often referred to as a ground plane. This ground plane can be the Earth itself, a metallic sheet, or a conductive platform such as the body of a vehicle […]

The Hertzian Monopole After establishing the image method for calculating fields in the upper half-space for antennas above a PEC ground plane, we can now apply these results to monopole antennas. Unlike dipoles, which have two feed terminals, monopoles are vertical wire antennas with a single feed terminal at the base, the other terminal being […]

Section A: Theoretical Proficiency 1. Who provided the unified theory of electromagnetism that first established light as an electromagnetic wave? 2. In a non-magnetic material medium, by what factor is the velocity of an electromagnetic wave reduced compared to its speed in a vacuum? 3. Why does the “Hairy Ball Theorem” prove that a perfectly […]