What is an interdigital capacitor?

What is an interdigital capacitor?

The interdigital (or interdigitated) capacitor is an element for producing a capacitor-like, high pass characteristic using microstrip lines. The shape of conductors is defined by the parameters shown in Figure 1. Since the conductors are mounted on a substrate, its characteristics will also affect performance.

What is capacitance physics?

Capacitance is the ability of a component or circuit to collect and store energy in the form of an electrical charge. Capacitors are energy-storing devices available in many sizes and shapes. The insulator is also known as a dielectric, and it boosts a capacitor’s charging capacity.

What are the function of interdigitated finger capacitor?

This example is an interdigitated capacitor composed of seven closely coupled parallel lines. This capacitor has a nominal value of about 0.1 pF below 1 GHz. As the frequency increases, the capacitor becomes more capacitive, due to the increase in fringing fields between the fingers.

What is capacitor and its unit?

Capacitors are widely used as parts of electrical circuits in many common electrical devices. Capacitance is expressed as the ratio of the electric charge (Q) on each conductor to the potential difference (V) between them. The SI unit of capacitance is the farad (F), which is equal to one coulomb per volt (1 C/V).

Do Capacitors store AC or DC?

Capacitors store charge or energy, not power. the charge and the energy are neither ac nor dc. the amount of charge or energy stored in a capacitor can vary from moment to moment. in a DC circuit, each instant is identical, so that the load is constant, like DC.

What is the principle of capacitor derive an expression?

Principle of a capacitor : A capacitor works on the principle that the capacitance of a conductor increase appreciably when an earthed conductor is brought near it. Thus a capacitor has two plates separated by a distance having equal and opposite charges.

How is the capacitance of an interdigital capacitor determined?

Interdigital capacitor is designed to be made by the microstrip lines on the PCB. Its capacitance is defined by the air gap between the electrodes. To correctly simulate the intergidital capacitor we need a full 3D analysis. However, for brief evaluation of the capacitance we may use 2D approach.

What kind of transmission line does interdigital capacitor use?

The interdigital capacitor frequently uses microstrip line planar transmission line because of easy of design and fabrication. The properties of this type of capacitor have been studied by many authors [3-7].

What kind of substrate is an interdigital capacitive sensor made of?

Typical interdigital capacitive sensors (IDC-S), are made of an ‘inert’ substrate over which the two comb electrodes are deposited. One chemical sensitive layer (usually a polymer) is then deposited over the electrodes.

How is the potential difference of a capacitor related?

The electric field in the region between the plates depends on the charge given to the conducting plates. We also know that potential difference (V) is directly proportional to the electric field hence we can say, This constant of proportionality is known as the capacitance of the capacitor.

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