Right now, the market houses multiple RF protocols, which are used for wireless communication. The IC industry has worked really hard to produce transceiver ICs for the common protocols. Based on the product you are planning to develop, you can work on a module, compact SoC, or a transceiver IC for covering your major needs. The most popular options will get to see the highest level of integration. However, not all items will be benefitted from the integrated module. Checking out the RF Amplifier Selection Guide is important before you can make way for the right approach.
In the case of wireless communication, the RF amplifier is a significant part of the RF front end and signal chain within your product. If you are just working your way as an RF engineer and need to work with an amplifier, look at the selection guide first. Understanding some important specifications is mandatory to know how they are going to affect the system.
Use of RF amplifier in front and back end:
Before you proceed further with the Types of RF amplifiers, you better understand the use of RF amplifiers within RF front and back end. There are different components, available in RF front end. It refers to circuitry that appears between the transmitter or receiver antenna and the digital processor.
- The RF front end, within a wireless product, works as a set of discrete components along with a higher integrated module set of ICs, and more. The RF amplifier appears within the Tx and Rx sides of the RF system.
- For that higher-power transmitter, a power RF amplifier is used on the Tx side. The Rx side at that time will use RF LNA to be added within the receiver.
- With a wide source of ICs and electronic components available on the market, the options remain practically endless.
- Most of the transceiver ICs will have a block diagram. On the Rx side, the RF LNA will bring the signal level up to major demodulation and runs well below saturation.
- On the other hand, the RF power amplifier on the Tx side is run closer to saturation to try and maximize power output in the desired frequency range.
- RF mixers are major parts of the conversion and modulator stages within the RF front end.
Later, the antenna switch can be seen used to swap between the TX and Rx legs of the signal chain. With MIMO systems, multiple antenna switches are used for sending out signals to various amplifier stages on Tx lines. Here, the modulation will get performed upstream from the switching stages.
Specifications to follow:
You might have probably heard about the Advantages of RF amplifiers, which is why these modules are getting so popular among the masses. Understanding the important RF specifications before that has been a necessity now. You have multiple specifications to pay close attention to and the major ones are listed within the RF Amplifier Selection Guide for your reference. However, among the whole lot, the major specifications are listed below for your better understanding.
· Gain flatness:
This section is different from bandwidth and gains alone but quite related. If you have designed anything like a dual-band system that needs to sweep across multiple frequencies, then you want to ensure a gain curve is relatively flat through the desired bandwidth. So, the gain of various types of RF amplifiers is mainly the function of frequency. So, the noise figure remains a frequency function too. The gain flatness might be specified as +/- variance in dB.
· The noise figure:
In any electronic system, noise is a part and parcel. The same rule is applicable in the RF signal chain. The noise figure within the RF amplifier will let you know how the input noise gets amplified because of the gain. There will be some decreases in the signal-to-noise ratio between the output and input, and those are unavoidable. Before focusing on the Advantages of RF amplifiers, dealing with the noise figure is a must. You need to jot down some functions of system bandwidth, which is one reason to limit the bandwidth with a higher-order bandpass filter.
On the Rx side, the LNA is not always a different form of RF amplifier. It is just an amplifier that provides a lower noise figure when compared to other options. In case you are designing for the Rx side, be sure to focus on the noise figure to capture a clean demodulated signal.
· 3IP Point and 1 dB compression point:
The OIP3 can be applied to any frequency-based modulated signal and even related to the 1 dB compression point of the High Power RF Amplifier. This specification holds major importance within power amplifiers on the Tx side as they operate near saturation.
The non-linear structure of the amplifier will create inter-modulation products and here, the 3rd order products are the vital ones. At some of the input power within the saturation regime, these 3rd order items will extrapolate to similar intensity as found within desirable sidebands.
· Gain and bandwidth:
Before you jump straight with the Linear RF Power Amplifier, understanding the gain and bandwidth characteristics is a necessity. RF amplifiers are mostly advertised depending on their gain within the specified frequency of bandwidth. These terms are mostly summarized as gain-bandwidth products with cut-off frequency. Even when the frequency is larger than desired frequency range, you can still get the chance to cut off noise within the system and also limit the bandwidth with a band-pass filter.
There are so much more that you need to know about RF amplifier before making the final choice. For that, the team from Elite RF is ready to help!
