Editing Amplifier (section)

=== Microwave amplifiers ===
[[Traveling wave tube]] amplifiers (TWTAs) are used for high power amplification at low microwave frequencies. They typically can amplify across a broad spectrum of frequencies; however, they are usually not as tunable as klystrons.<ref>{{Cite web|url=http://www.r-type.org/articles/art-030.htm|title=Travelling Wave Tube Amplifiers|website=www.r-type.org|access-date=2016-06-20}}</ref>

[[Klystron]]s are specialized linear-beam vacuum-devices, designed to provide high power, widely tunable amplification of millimetre and sub-millimetre waves. Klystrons are designed for large scale operations and despite having a narrower bandwidth than TWTAs, they have the advantage of coherently amplifying a reference signal so its output may be precisely controlled in amplitude, frequency and phase.{{Cn|date=December 2024}}

[[Solid-state device]]s such as silicon short channel MOSFETs like double-diffused metal–oxide–semiconductor (DMOS) FETs, [[Field effect transistor|GaAs FET]]s, SiGe and GaAs [[heterojunction bipolar transistor]]s/HBTs, [[HEMT]]s, [[IMPATT diode]]s, and others, are used especially at lower microwave frequencies and power levels on the order of watts specifically in applications like portable RF terminals/[[cell phones]] and access points where size and efficiency are the drivers. New materials like gallium nitride ([[GaN]]) or GaN on silicon or on [[silicon carbide]]/SiC are emerging in HEMT transistors and applications where improved efficiency, wide bandwidth, operation roughly from few to few tens of GHz with output power of few watts to few hundred of watts are needed.<ref>{{cite journal|title= Introduction to the Special Section on the IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS 2008) | volume=44 |issue= 10 |journal=IEEE Journal of Solid-State Circuits |pages=2627–2628|year= 2009 |last1= Peatman |first1= W.C.B. |last2= Daniel |first2= E. S. | doi=10.1109/JSSC.2009.2029709 | bibcode=2009IJSSC..44.2627P }}</ref><ref>{{cite book|doi =10.1109/VLSI-DAT.2017.7939653 |pages=1–3|year= 2017 |last1= Lie |first1= D.Y.C. |last2= Mayeda |first2= J. C. |last3= Lopez |first3= J. |title=2017 International Symposium on VLSI Design, Automation and Test (VLSI-DAT) |chapter=Highly efficient 5G linear power amplifiers (PA) design challenges |isbn=978-1-5090-3969-2 |s2cid=206843384 }}</ref>

Depending on the amplifier specifications and size requirements microwave amplifiers can be realised as monolithically integrated, integrated as modules or based on discrete parts or any combination of those.{{Cn|date=December 2024}}

The [[maser]] is a non-electronic microwave amplifier.{{Cn|date=December 2024}}