Integrated Filter–Amplifiers: A Comprehensive Review
Yang Gao, Xiaobang Shang, Lei Li, Cheng Guo, Yi Wang
Abstract
Amplifiers and filters are essential components in microwave systems. An amplifier is used to increase the signal strength, and it is usually cascaded by filters for frequency selection or harmonic rejection <xref ref-type="bibr" rid="ref1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[1]</xref> – <xref ref-type="bibr" rid="ref2" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> <xref ref-type="bibr" rid="ref3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[3]</xref> . Their functionalities require a precise design of the individual parts as well as the way in which they are connected. The common approach is to make individual components with a system impedance that is usually <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${50}\Omega{.}$</tex-math></inline-formula> A generic example of the filters and amplifier in a generalized receiver is shown in <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1(a)</xref> .