engineering

Monolithic microwave integrated circuit

Monolithic microwave integrated circuit is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Monolithic microwave integrated circuit rather than just read about it. In short: Monolithic microwave integrated circuit, or MMIC (sometimes pronounced "mimic"), is a type of integrated circuit (IC) device that operates at microwave frequencies (300 MHz to 300 GHz). These devices typically perform functions such as microwave mixing, power amplification, low-noise amplification, and high-frequency switching.

Key takeaways

Monolithic microwave integrated circuit belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Monolithic microwave integrated circuit to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Monolithic microwave integrated circuit from memory before moving on to harder problems.

Reference excerpt

Monolithic microwave integrated circuit, or MMIC (sometimes pronounced "mimic"), is a type of integrated circuit (IC) device that operates at microwave frequencies (300 MHz to 300 GHz). These devices typically perform functions such as microwave mixing, power amplification, low-noise amplification, and high-frequency switching. Inputs and outputs on MMIC devices are frequently matched to a characteristic impedance of 50 ohms. This makes them easier to use, as cascading of MMICs does not then require an external matching network. Additionally, most microwave test equipment is designed to operate in a 50-ohm environment. MMICs are dimensionally small (from around 1 mm2 to 10 mm2) and can be mass-produced, which has allowed the proliferation of high-frequency devices such as cellular phones. MMICs were originally fabricated using gallium arsenide (GaAs), a III-V compound semiconductor. It has two fundamental advantages over silicon (Si), the traditional material for IC realisation: device (transistor) speed and a semi-insulating substrate. Both factors help with the design of high-frequency circuit functions. However, the speed of Si-based technologies has gradually increased as transistor feature sizes have reduced, and MMICs can now also be fabricated in Si technology. The primary advantage of Si technology is its lower fabrication cost compared with GaAs. Silicon wafer diameters are larger (typically 8" to 12" compared with 4" to 8" for GaAs) and the wafer costs are lower, contributing to less expensive IC. Originally, MMICs used metal-semiconductor field-effect transistors (MESFETs) as the active device. More recently high-electron-mobility transistor (HEMTs), pseudomorphic HEMTs and heterojunction bipolar transistors have become common. Other III-V technologies, such as indium phosphide (InP), have been shown to offer superior performance to GaAs in terms of gain, higher cutoff frequency, and low noise. However, they also tend to be more expensive due to smaller wafer sizes and increased material fragility. Silicon germanium (SiGe) is a Si-based compound semiconductor technology offering higher-speed transistors than conventional Si devices but with similar cost advantages. Gallium nitride (GaN) is also an option for MMICs. Because GaN transistors can operate at much higher temperatures and work at much higher voltages than GaAs transistors, they make ideal power amplifiers at microwave frequencies.

See also Hybrid integrated circuit Transmission line

References Practical MMIC Design, Steve Marsh, published by Artech House ISBN 1-59693-036-5 RFIC and MMIC Design and Technology, editors I. D. Robertson and S. Lucyszyn, published by the IEE (London) ISBN 0-85296-786-1

Illustrations

Worked examples

Example 1 — a first encounter with Monolithic microwave integrated circuit

Start with the simplest possible case. Write down what Monolithic microwave integrated circuit claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Monolithic microwave integrated circuit before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Monolithic microwave integrated circuit ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Monolithic microwave integrated circuit

In research: Monolithic microwave integrated circuit appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Monolithic microwave integrated circuit in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Monolithic microwave integrated circuit is common in secondary-school and first-year university syllabi. It links to neighbouring topics Integrated circuits, Microwave technology, so understanding it makes those chapters shorter.
In everyday life: Look for Monolithic microwave integrated circuit outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Monolithic microwave integrated circuit in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Monolithic microwave integrated circuit means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Monolithic microwave integrated circuit out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Monolithic microwave integrated circuit in simple terms?

Why does Monolithic microwave integrated circuit matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Monolithic microwave integrated circuit?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Monolithic microwave integrated circuit.