Understanding RF Coax Cables And RF Amplifiers

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Understanding RF Coax Cables And RF Amplifiers

Ironically, many RF coax cables designers still believe that the cheapest way to find a coax cable is to find a coax cable assembly and then make it work. This trick may have been valid in the past, but it is no more valid in today’s time. The lead times of custom coaxial solutions cost no more than the standard one. This applies to all RF components.

The industry is way more automated today with the high-tech equipment used in the production and innovative applications. The attempts to shoehorn a standard solution into the custom one is literally not required. It is, however, imperative to understand the basic anatomy of coax cables.

Coax cables

Coax cables are known for being broadband which incorporates low-loss and high isolation transmission line technology. There are two concentric conductive cylinders in these cables which are separated by a dielectric spacer.

The disturbed impedance called characteristic impedance is created throughout the structure by distributing capacitance and inductance along the coaxial line. These cables are used to transmit electromagnet energy with less loss than a free space propagation by the antenna.

Application Of Coax Cables

The application potential of these cables is defined by the few frequency-dependent behaviors including skin depth and cut off frequency. A phenomenon which occurs for signals at a higher frequency when traveling through the coaxial line is called skin depth. More electrons travel towards the conductors’ surface of a coaxial line when the frequency is high. It increases attenuation and dielectric heating which results in a greater resistive loss. To reduce this loss, a larger diameter cable can be used. This phenomenon remains the same as the RF coax cables too.

When the size of the wavelength of electromagnet energy is more than the transverse electromagnetic mode the cut-off frequency is created, this new mode is troublesome because it has a different velocity which can cause reflections and interference to the signals traveling through the line.

RF amplifier

There are various types of these amplifiers, and it is important to know about them before deciding what suits you best. We are discussing a few of the types here:

Broadband Amplifiers

They offer moderate gain over a wide bandwidth and maintain a low noise figure. They are often used within receiver circuitry placed at the front of the antenna.

Gain Block Amplifiers

They are similar to the broadband amplifiers, but the only exception is they are not designed for the low noise figure and have a greater gain. Narrow bandwidths and wide bandwidths models are included which depends on the application they are designed for.

Log Amplifiers

This type of RF amplifier has a gain curve when a natural log of input voltage has a multiple output voltage.

Wrap Up

There are many more types, and each is important depending on the use and application. No matter how innovative transmitting and receiving has become the importance of RF components is still undeniable. They are still used efficiently, and there is no end to their usage in the near future.



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