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Capacitive sensor - coupling with circuit

Posted May 17, 2013, 11:07 a.m. EDT RF & Microwave Engineering Version 4.3a 2 Replies

Rüdiger Hansen
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Hello,

I build a small model of a capacitive sensor (small conducting plate). An electric dipole serves as the source of an electric field.

The field induces a surface current density at the sensor plate. But i cannot figure out how i couple this current with an attached circuit (see attached figure of circuit).

I tried lumped ports (electrical circuit module) and terminals (electric currents module), and coupled those with an external I vs U node.

But since the sensor only has one contact (one node, see figure) I don't think lumped ports and external I vs Us are approriate.

Would be nice if someone could give me a hint. Thanks.


2 Replies Last Post May 18, 2013, 6:41 a.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago May 17, 2013, 4:40 p.m. EDT

Hi Rüdiger,

I have a couple of comments:

1. The ground you indicate in the circuit must some way have a counterpart in the model. The current must have a path to flow back into the geometry.

2. Your model dimensions are much smaller than the wavelength. A couple of cm versus 300 m at 1 MHz. So you should use AC/DC instead of RF. A PML is useless, you don't have waves in your model.

3. In AC/DC you should probably use terminals. You define your electrode as a terminal and you must define a ground in your model geometry

Cheers
Edgar

--
Edgar J. Kaiser
www.emphys.com
Hi Rüdiger, I have a couple of comments: 1. The ground you indicate in the circuit must some way have a counterpart in the model. The current must have a path to flow back into the geometry. 2. Your model dimensions are much smaller than the wavelength. A couple of cm versus 300 m at 1 MHz. So you should use AC/DC instead of RF. A PML is useless, you don't have waves in your model. 3. In AC/DC you should probably use terminals. You define your electrode as a terminal and you must define a ground in your model geometry Cheers Edgar -- Edgar J. Kaiser http://www.emphys.com
Rüdiger Hansen
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Posted: 1 decade ago May 18, 2013, 6:41 a.m. EDT
Thanks. I'll give it a try.

Best regards.
Thanks. I'll give it a try. Best regards.

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