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Ever used piezo ignition for your gas stove or oven? https://en.wikipedia.org/wiki/Piezo_ignition

This is using the same property: you press a button (usually hard!) to deform a crystal and as a result you get a nice little spark due to a (brief) high voltage.

So if you deform the crystal, you get a voltage. You can also apply a voltage to deform the crystal.

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MMICs (or "mimics") are Monolithic Microwave Integrated Circuits designed for use in the 300 MHz to 300 GHz frequency range. They are typically designed to have a characteristic impedance of 50 ohms at both the input and output. This allows them to be cascaded in a circuit without the need for additional impedance matching components. This impedance also matches most up with most microwave test equipment allowing for easier connections.

Hint: MMIC's "mimic" the common impedance of your transmission line

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Noise figure (NF) is the ratio between the noise the receiver produces and the theoretical minimum noise for a perfect receiver:

\[\text{noise figure}=\frac{\text{receiver noise}}{\text{theoretical minimum noise}}\]

Since it is a ratio, and each value is measured in dB, dB will cancel. We can thus eliminate both values given in dBm.

Real-world receivers can never be as good as a perfect receiver, so the noise figure ratio will always be greater than unity. If this ratio is strictly positive, we cannot have negative values.

The only remaining answer is 2 dB.

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Microstrip transmission lines consist of a conductive strip of width "W" and thickness "t" and a wider ground plane, separated by a dielectric layer (a.k.a. the "substrate") of thickness "H" as shown in the figure below. Microstrip is by far the most popular microwave transmission line, especially for microwave integrated circuits and MMICs. The major advantage of microstrip over stripline is that all active components can be mounted on top of the board.

TIP: MICROwave = MICROstrip

www.microwaves101.com/encyclopedias/microstrip

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Load capacitance is an important specification when using parallel-resonant oscillation mode.

http://www.maximintegrated.com/en/app-notes/index.mvp/id/726

Silly memory aid: provide "Crystal" with a "cap" (capacitance).

or, looks like crystals in the ice cap of the mountain

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The correct answer here is that a quartz crystal's equivalent circuit is a series RLC circuit in parallel with a shunt capacitor, \(C_p\), which represents electrode and stray capacitance.

Explanation:

1. Series RLC: The quartz crystal itself can be modeled as a series RLC (resistor-inductor-capacitor) circuit due to the mechanical vibrations it undergoes. The resistance \((R)\) models energy losses, the inductance \((L)\) represents inertia in the crystal's oscillations, and the capacitance \((C)\) is linked to its elasticity.

2. Shunt Capacitance \((C_p)\): This shunt capacitor models the capacitance between the crystal's electrodes and any additional stray capacitance from the surrounding circuit. It is placed in parallel with the series RLC to represent the full behavior of the crystal in a circuit.

3. Resonant Frequencies: This configuration supports two resonance points—series resonance and parallel resonance. At series resonance, the series RLC impedance is at a minimum, and the crystal operates as a low-impedance path. At parallel resonance, the combined effect of the series RLC and \(C_p\) creates a high-impedance path, setting the parallel resonant frequency.

Incorrect answers suggest either purely parallel configurations or series/parallel combinations that don’t match the actual behavior of the crystal's resonant properties.

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Memory tips:

1. The only answer that includes the mention of a shunt capacitor is the correct choice.
2. equivalent circuit means a circuit that replaces the quartz crystal.
3. The only correct answer does not include crystal

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MMIC = Monolithic microwave integrated circuit

From Wikipedia:

Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor commonly used in bright light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic[4][5], high-power and high-frequency devices. For example, GaN is the substrate which makes violet (405 nm) laser diodes possible, without use of nonlinear optical frequency-doubling.

Its sensitivity to ionizing radiation is low (like other group III nitrides), making it a suitable material for solar cell arrays for satellites. Military and space applications could also benefit as devices have shown stability in radiation environments.[6] Because GaN transistors can operate at much hotter temperatures and work at much higher voltages than gallium arsenide (GaAs) transistors, they make ideal power amplifiers at microwave frequencies. (Emphasis added)

An easy way to remember this one is it is the only non-Silicon answer.

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Think "Indiana Jones and the Kingdom of the Crystal Skulls"

The Jones Filter is a special type of crystal lattice filter that allows for a variable bandwidth.

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