Coaxial cables are an essential component in the RF/microwave industries. They connect essential elements varying from smartphones and laptops for daily life to radar and GPS for military and aerospace.
For practically every application, it is complicated to transmit signals from one component to another while keeping adequate signal integrity. Adding complex and dynamic signal routes need a flexible platform for adapting to various conditions and applications. One alternative to this problem was proposed by the famous engineer and mathematician Oliver Heaviside. In 1880, he patented a design for a shielded telegraph transmission line.
In 1929, Herman Affel and Bell Labs’ Lloyd Espenschied and invented the broadband coaxial cable with an air-like dielectric spacer. Since then, coaxial-cable technologies have improved in both materials and efficiency, supplying solutions for many RF/microwave/millimeter-wave interconnection difficulties.
Factors to consider
The various variations of coaxial cables meet different electrical and mechanical performance requirements. The frequency and power requirements determine the physical dimensions of a coaxial cable.
The standard basic version of a coaxial cable is made of a center conductor, which is mechanically separated from a cylindrically symmetric conducting shield by an air-like dielectric. The geometry of this conductor enables electromagnetic signals under a maximum cutoff frequency to create a transverse-electromagnetic wave within the separation space between the conductors.
Cable weight and material use can be minimized with a dielectric spacer’s employment, which grips the groves in a corrugated center and external conductor. In doing so, it keeps the coaxial nature of the cables.
The materials utilized to assemble coaxial cable may vary, electrically, as a purpose of vibration, temperature, moisture, current, flexure, and strain. These variations alter the cable’s performance. Also, there is the skin effect—a physical phenomenon that illustrates the increased distribution of electrons traveling near the surface of a conductor as the frequency of the signal is increased. The skin effect makes the signal traveling through a coaxial cable vulnerable to imperfections in the conductor surface finish.
As a result of these sensitivities, coaxial-cable manufacturers have formulated advanced methods and materials to guarantee the highest possible efficiency while meeting cost, weight, flexibility, loss, and ruggedness requirements. The dielectric spacer inside a coaxial cable is crucial, as it preserves the coaxial geometries of the two conductors with the added difficulty of functioning as much like air as possible. Being air-like means having almost the same magnetic permeability and electric permittivity of air.
Numerous shielding layers can be added to a standard coaxial cable to improve isolation and decrease interference in the signal path.
For low-cost purposes, like cable television, minimum braiding is utilized to decrease cost, weight, and size. Cable manufacturers employ a variety of material types based on performance, cost, and manufacturability objectives. Center conductors are commonly silver-plated copper, though tin-plated copper is also applied. In lightweight applications, the most common materials used are Silver-plated and copper-clad aluminum. The materials used for coaxial shields can vary and include formed beryllium copper, silver-plated copper, and metalized polymers.
If you would like to receive a quote for any of custom cables or connectors, please do not hesitate to contact us by sending an email to [email protected] or calling in the USA this phone number (682-325-1944).