At first glance, you might notice that there are many different types of RF amplifiers, and it sometimes becomes overwhelming to differentiate between each one. This makes narrowing down your RF amplifier type a very difficult job.
Most RF Amplifiers came about due to specifications from common transceivers, transmitters, radars, modulation circuits, and system level typologies. It is fair to say that all these specifications sound confusing at times. This article aims to solve that confusion and provide you with information about the purpose of these Amplifiers, and their applications. So, let us begin:
Broadband or wideband amplifiers are designed to provide a moderate transmission gain over longer bandwidths while keeping the noise figure low. These amplifiers are primarily used within the receiver circuity at the front-end of the antenna, where the requirement for low noise amplifiers is not present.
Gain Block Amplifiers
Gain block amplifiers are similar to broadband Amplifiers, with just a few exceptions. They have a greater gain than broadband amplifiers and are not designed for low noise. You can use gain block amplifiers for IF, RF, and microwave transmitter applications. It also includes models with narrow or wide bandwidths. This is dependent on the type of applications they are designed for.
A log amplifier is an amplifier that provides a greater gain curve where the output is a natural log of the input voltage. This type of amplifier is required for applications that specify such requirements.
Variable Gain Amplifiers
Variable gain amplifiers are amplifiers that provide a controllable and often times, a programmable gain. They have built-in variable gain circuits or variable attenuators, depending on the application, to provide such a gain. They are used primarily for closed-loop circuit control for the maintenance of consistent signal power level.
Low Noise Amplifiers
Low noise amplifiers leverage a portion of the transmitter or receiver design where a low-power signal needs to be amplified for a working power level, without introducing significant noise or phase noise. This could be an oscillator output, which strengthens a signal to drive a mixer, or at the input of an antenna to increase a signal’s power to be easily processed by demodulation or digitization of currency.
Coaxial and Waveguide Power Amplifiers
Within the RF front-end transmitters, power amplifiers are considered as the workhorse amplifiers which convert smaller power signals from communications and radar equipment to high powered transmissions sent through an antenna. The goal of a power amplifier is to increase the digital gain of a signal to a higher power level, without facing a reduction in signal quality. This is typically a hard designed challenge that has many tradeoffs, and certain power amplifiers can be optimized for parameters that befit the pulsed radar, CW radar, digital communication systems, or any application for which they are required.
Power amplifiers also contend with handling different types of loads, some which could cause damaging reflections. Hence, power amplifier designs are usually included with protective circuits. If their power level or operational frequency is high enough, power Amplifiers can use coaxial connectors or even waveguide connectors.
A linear amplifier is a type of RF power amplifier, which is specially designed to provide high-quality linear performance, maintaining the proportional linear relationship of inputs and outputs. Linear amplifiers are designed to optimize linearity over other design considerations, especially in different load conditions. They are used primarily for transmitters and tests equipment when higher linear power is required.
Bi-directional amplifiers are a combined form of transmitter and receiver, designed solely for the purpose of acting as an intermediate node receiving weak signals and amplifying it for retransmission at a distant location. The primary use of bidirectional amplifiers is for the extension of communication networks across remote locations without having to install extra transmission lines to boost the signal. It can also be used for covering overland areas or used alongside coaxial assembly lines to extend signals to several distances or within facilities. Bi-directional amplifiers require good performance and low-noise amplifiers. It is modeled to handle high digital communications to ensure the highest signal power at the destination point.
Hi-Rel amplifiers are a class of amplifiers that meet or exceed a higher reliability standard or expectation, usually employed for use within the automotive, aerospace, space, or military application. These amplifiers, because of their specialized use, are often higher in resilience than their standard counterparts. They also have ratings that include the likely lifespan of an amplifier under various operational conditions.
Now that we have provided you with an overview of the types of amplifiers, it is time to move towards a discussion of industry-level amplifiers.
Picocell Amplifiers used best for SM, EDGE, LTE, and CDMA operations include models with 750MHz, 760MHz, 850MHz, 900MHz, 1800MHz, 1900MHz, and 2100MHz. The models are categorized into various bands that provide a power of 15 to 30 Watts.
These amplifiers provide TX power to the uplink and an RX gain to the downlink frequencies of the mobile base station. The units are connected directly to the carrier. The compact size and ease of installation make them best suitable for use in rapid deployments of small and microcellular base operations. The pico cell amplifier can have applications in remote/ isolated locations, marine & aviation, public spaces, disaster-hit areas, rural spaces, and oil and gas.
The amplifiers provide full duplex operation, ensuring uninterrupted voice and data connections. The product line is single pole mounted, fully conditioned with the weather and watertight power connections. The amplifier provides two inputs: one for uplink frequency and the other for downlink frequency.
Industrial bi-directional amplifiers come in different shapes and sizes. They are usually weatherproof amplifiers providing usage for all outdoor applications. They are available in PCB version for OEM customers for the following frequencies: 300-500, 700, 900, 1300, 2400, 3500, 4400-5000, and 5700-5800. Best for small housing where limitations of space exist. The primary features of these bi-directional amplifiers are as follows:
- They provide higher transmit gains with the help of the latest Gallium Arsenide Transistor. It results in a highly linear gain.
- Keeping the noise level very low, the built-in low noise amplifier RX signal improves the receive sensitivity of remote equipment.
- This amplifier’s bandwidth pass filter provides extra protection against out of band noise.
- The coax housing surrounding the amplifier does not require mounting hardware and seals with watertight strength with a twist of the hand.
- Requires only 5 watts of power consumption during the maximum transmission period, saving energy in the process.
- Its DC Injector has only 1.2 Decibels of insertion loss. The BDA SC injector has the lowest RF impact rates, which ensures high performance.
- The product comes with a 2-year warranty.
The LNA series are wide-band low noise amplifiers that operate with different frequencies depending on the ranges. The gain starts at 11 dB and goes up to about 50 dB with the frequencies ranging from 10MHz to 6500MHz. The low noise range can operate as low as 0.55 dB and can be as low as 3.5 dB. Some key features of these amplifiers are:
- Widened operational frequencies.
- 55 dB minimum low noise.
- SMA gold plated connectors.
- Flexible power options.
The state of the art single band repeater amplifiers boost signal strength and improve cellular communication without a physical cell phone connection. This amplifier has a typical signal gain of 60 dB which is controlled automatically using proprietary digital design. You will usually see this type of amplifier installed in large yachts, homes, and offices.
The cellular repeater amplifier works through an outside antenna which is connected outside the premises, and which receives the signal from the base station. The cell amplifying unit boosts the signal and forwards it to the cell phones through an inside antenna, which is placed inside the premises. Because of this system, you have the freedom to walk while talking on your phone. The technology allows clean and clear wireless functioning of multiple cell phone connections operating at 800MHz or 1900 MHz bandwidths. The key features of these amplifiers are:
- Plug and Play
- Higher Gain
- FCC (USA) certified
- Consumes less power
- Supports a wide range of network signals, including GPRS.
The DC coupled amplifier series is a 50 Ohm DC amplifier that offers gain from 8 dB to 30 dB and operate within a 3 dB bandwidth of 2000MHz. It is designed for wide-band signal processing. The key features of this product are:
- Wideband signal options
- 50 Ohms of input/output
- SMA gold-plated connectors
- Flexibility in power options.
The SPA series of amplifiers are high performance and high-reliability RF amplifiers that operate within different frequency ranges. Besides being a wideband amplifier, there are several features that you can look out for with the SPA:
- 40-43 dB high power gain.
- High-frequency wide band from 700 to 960 MHz.
- Consumption of power less than 36W.
The HPA Amplifiers are very similar to the SPA series of amplifiers with the exception that their frequency bands range from 1000-1300MHz.
The LRA series have high reliability and higher performance in their amplification. They operate within different frequencies and have the following features:
- Gain is low-powered
- Available in multiple frequency ranges
- Less than 2 Watts of power consumption
The MGA series of high-performance amplifiers provide you the reliability and endurance that you would expect from an amplifier. Its operation ranges include medium power gain, low power consumption, and an operating temperature of -40 to 70 degrees Celsius. Other key features of this amplifier include:
- Medium power gain ranging from 10 to 33 dB
- Power consumption is less than 5 Watts
- Frequency range is from 40 to 5450 MHz
The MPA Amplifier series are wide-banded high-performance RF-type Amplifiers that operate in a multitude of frequency ranges. Some of its key features include:
- A 28 to 42 dB of medium to high power gain
- Less than 22 Watts of power consumption
- Frequency range from 30 MHz to 5900 MHz
The MRA series is similar to the MPA series. The only difference between the two is that they operate at different frequency ranges and operating temperatures. Some of the features of this product are:
- Operating temperatures from -54 to 85 degrees Celsius.
- Power gain ranging from 10 to 18 dB.
- Frequency range from 10 to 2600 MHz.
- Less than 5 Watts of power consumption.
In this article, we discussed amplifiers. More specifically, we talked about what are amplifiers, their purpose, their different specifications, their types, and their application. For the sake of simplicity, we divided this article into two phases. The first one discussed the various types of amplifiers, like bi-directional and linear amplifiers. We talked about what makes these amplifiers special in their own regard. In the next part, we talked about the famous industrial amplifiers and their key features. Hopefully, this article would have been able to provide you with a thorough description of amplifiers.