Receiver Antenna in SPICE - RF Cafe Forums

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jdirga

Post subject: Receiver Antenna in SPICE Posted: Wed Apr 15, 2009 1:13 pm

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Joined: Wed Apr 15, 2009 12:58 pm

Posts: 5

I need to include a receiver antenna in SPICE simulation. Should I model it as a current source or voltage source? Does this depend on the type of antenna (whether it's a dipole, loop, etc) that I use? Please help. Thx.

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RDO-RF

Post subject: Re: Receiver Antenna in SPICEPosted: Wed Apr 15, 2009 4:19 pm

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Joined: Wed Apr 08, 2009 7:53 am

Posts: 12

I think you can manage to use any of those sources as long as it has the correct internal characteristic impedance of your system.

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IR

Post subject: Re: Receiver Antenna in SPICEPosted: Wed Apr 15, 2009 4:40 pm

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Joined: Mon Jun 27, 2005 2:02 pm

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Location: Germany

Antenna should be simulated as voltage source. The type of antenna does not matter for the SPICE simulation.

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- IR

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jdirga

Post subject: Re: Receiver Antenna in SPICEPosted: Wed Apr 15, 2009 8:11 pm

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Joined: Wed Apr 15, 2009 12:58 pm

Posts: 5

Thanks for all the replies. Could you give a reason why it should be modeled as a voltage source instead of a current source?

My original thought was if it were a loop antenna, it should be modeled as a voltage source because the signal is generated on the received antenna thru Faraday's law of induction, i.e. emf=change of flux. However if it were a dipole, it should be modeled as a current source because signal is generated due to lenz's law?(I'm not confident with this).

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IR

Post subject: Re: Receiver Antenna in SPICEPosted: Fri Apr 17, 2009 4:05 pm

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Joined: Mon Jun 27, 2005 2:02 pm

Posts: 373

Location: Germany

Why a voltage source? good question.

1. In all of the RF text books I have encountered Antenna is modeld as voltage source, transmitter is modeled as voltage source with Thevenin resistnce etc (On the other hand it also could have been modeled as a current source...). So it is a matter of industry convntion, also the case for: VSWR, S-parameters etc.

2. If you want to add a noise source to the simulation (Which is very common in simulatin an Antenna circuit) you will also have to model it through a voltage source and its associated noise resistance - Johnson noise model. In this case it is easier to combine the signal voltage with the noise voltage rather than a current signal with noise voltage.

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jdirga

Post subject: Re: Receiver Antenna in SPICEPosted: Sat Apr 18, 2009 10:35 am

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Joined: Wed Apr 15, 2009 12:58 pm

Posts: 5

I am hoping to know the physical reason why normally reception antenna is modeled as a voltage source.

Whether it's a voltage source or current sources matters in my simulation, for example, in transient simulation, if voltage source is used, when the voltage source reaches, let's say, 1mV and the capacitive load is already charged up to 1mV, current will no longer flow because there's no voltage difference. However, when current source is used, current will flow to the capacitive load no matter what.

Posted  11/12/2012