MMIC
This page describes MMIC,its biasing technique and MMIC manufacturers/suppliers.
Microwave IC can be made either by hybrid technique or by monolithic technique on a variety of dielectric substrate materials. In a hybrid IC, circuit inter-connections are done using metal lines deposited on insulating substrate. In a Monolithic IC, all the components are formed using various processes which include diffusion or ion implantation. This changes the physical properties of the substrate material. Inter-connections in this hybrid MIC is done similar to thin film hybrid ICs. In a monolithic microwave IC, active devices are fabricated in a single block of semiconductor and they are connected via metal lines/wires.
Description
As mentioned MMIC is the short form of Monolithic Microwave Integrated Circuit. There are different MMICs are available for different functions such as for mixing, for amplification and so on. Various materials have been used to build MMIC, among them are GaAs (gallium arsenide), InP (Indium Phosphide), GaN (Gallium Nitride), SiGe (Silicon Germanium).
Biasing the MMIC
We will see passive biasing configuration here for silicon bipolar MMIC amplifier.
Other than matching MMIC to the 50 Ohm line, the critical part is how to bias the MMIC to get best results. This is explained here.
As shown in the figure, RF designer need to check specific data sheet of MMIC for example MSA 1110 device or ERA series from minicircuits.
MMIC bias resistor Equation
Ib= (VCC-Vd)/Rb
Where Ib is the bias current, Vcc is the supply voltage, Vd is the device voltage and Rb is the bias resistor.
Vd,Vcc,Ib is usually provided in the data sheet of the amplifier device.
Popular MMIC Manufacturers/Suppliers
1.General Purpose wideband MMIC amplifier from Mini circuit.
To search specific MMIC device based on the specification
2. GaAs MMIC from Hittite for various functions such as gain blocks, for low noise amplification, linear power and for wideband applications.