We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is a Loop Antenna?

By Shannon Cam
Updated May 16, 2024
Our promise to you
EasyTechJunkie is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At EasyTechJunkie, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A loop antenna is an antenna that creates a continuous conducting path between one conductor of a two-wire transmission line to the other. There are three categories of loop antenna: small, medium, and large. A small loop is considered so if its circumference is less than one forth of a wavelength. Most directional receiving loops are approximately one tenth of a wavelength.

A small loop is sometimes referred to as a magnetic loop, due to its increased sensitivity to the magnetic components of an electromagnetic wave. It is also less sensitive to nearby electric noise than other antennas, when properly shielded. If a small loop is brought into resonance with a tuning capacitor, its received voltage can be greatly increased. When a signal arrives along the loop's axis, an equal amount of voltage will be induced in each limb to account for symmetry. Since the loop's output is the difference in voltage between the two limbs, it should always be zero. If a signal arrives in the plane of the loop, it creates a phase difference between the limb voltages. These signals produce the maximum output for a small loop.

There are two specific cases when a loop antenna is classified as a medium loop. As such, these cases have specific characteristics. The first case occurs when a half-wavelength loop is mounted in a horizontal plane. This creates a horizontally polarized omnidirectional antenna, an antenna which radiates power uniformly in the horizontal plane. The second case is that of a full-wavelength loop that radiates on its axis. These loops are often found as elements of the quad antennas used by amateur radio operators. They are polarized according to the position of their feed point.

A large loop antenna is essentially a dipole antenna that has been connected at the ends to form either a circle, a triangle, or a square. Those formed into triangles are called delta loop antennas. The circular loops gets about ten percent higher gain than any of the other forms, but they can be difficult to support because of their shape. It is for this reason that triangle and square large loops are so much more common. Large loops usually have much stronger signal in the plane of the loop, rather than along the axis. This remains true as long as the loop is not too large.

Some loop antennas can also be tuned to the AM broadcasting band. An AM loop antenna is usually tuned with a capacitor. They may also be wound around a ferrite rod to increase aperture. Ferrite is a ceramic material used in applications ranging from magnetic components to microelectronics. Antennas wound around these rods are commonly referred to as loopstick antennas, due to the shape of the wire. These antennas work well for receiving but are inefficient and impractical for transmitting.

EasyTechJunkie is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Discussion Comments

EasyTechJunkie, in your inbox

Our latest articles, guides, and more, delivered daily.

EasyTechJunkie, in your inbox

Our latest articles, guides, and more, delivered daily.