Antennas, Waveguide & Cables

Antennas

The transmitter unit's signal is converted into electromagnetic waves radiating from an antenna. The reverse occurs at reception when the antenna receives electromagnetic waves and converts them into a signal to be further processed by the receiver.
 
Antennas are used in radio and TV broadcasts as well as in radio communication, radar, mobile telephony and satellite communication. Parameters such as frequency band, power, radiation direction are optimized for the best efficiency in the specific application. Antennas can be designed to be radiate in one direction or in different directions with different gain factors. Examples of common antenna types are multi-element, satellite and horn antennas.

 

Rotary Joints  

Rotary joints are used where there is a need to transmit RF signals between stationary and moving parts of a system, for example in radar applications or land mobile radio.

Important for a rotary joint is VSWR (Voltage Standing Wave Ratio), insertion loss and that the RF signal is kept stable during rotation. Rotary joints are available for connection either with coaxial connectors or waveguides.

 

Wave guides

Radio and microwaves are around us in everyday life, such as in the microwave oven, around cell phones and satellite communication. Microwaves are part of the electromagnetic spectrum between radio frequency and infrared light. In the free state, radio and microwaves propagate in all directions. A waveguide captures the microwave energy and transmits it in a direction with minimal losses.

A waveguide is designed as a hollow metal tube and transmits microwave energy like the coaxial cable does for radio frequencies. In the same way that there are a variety of coaxial connected components for processing signals, there are corresponding components with waveguide connections. It is possible to use coaxial cable or waveguide over a wide frequency spectrum from RF up to about 70 GHz. The choice between cable and waveguide is based on transmission distance and frequency band. Waveguides tend to be very large at low frequencies because of the wavelength of the signal but are often used when high effects are to be handled. For some applications, it is advisable to use flexible waveguides that are flexible to a certain radius and allow for flexible installation. The various systems can also be connected through a WG / Coax adapter which is made up of a waveguide connection with a suitable type of coaxial contact at the other end.
 

Coaxial Connectors, Adapters and Cables

Coaxial RF connectors are designed to operate at frequencies in the MHz or GHz range. They are used together with coaxial cable and are designed to maintain the best shielding with the cable. There are two main type of connections; threaded or bayonet-mounted. Different connectors are optimized for different frequency bands and power ratings.

Examples of contacts are F, BNC, TNC, 1.0 / 2.3, MCX, 7/16, SMA, N, 4.3-10, 3.5 mm, 2.92 mm and 2.4 mm.

Adapters make transitions between different types of contacts possible, or for adaptation between male and female contacts.
 

Coaxial cables are adapted for specific frequency bands, effects, signal losses and shielding. Some are very flexible while others are more rigid. Rigid cables are used in fixed designs where the cables do not need to be moved as often. The cable consists of an inner conductor surrounded by insulating layers and shielding. Cables can be optimized for different requirements such as low losses, phase matching, low intermodulation, impedance and reflection. Mechanical design is also important in applications where the cable is used more frequently and is subjected different types of stress.

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