Good Ideas for IC for Beginners

Nice answer Del.

(I hate RF)

And a GA from me for that!

We need more clarification as Del mentioned but I must warn the OP.

Antenna theory and design is one of the few analog realms that will never be superseded by digital design. As such it is one of the truly practical fields that one can learn analog circuit theory. However, the marriage of digital circuits with antennas is not a realm that I would recommend as a starting point for any beginner familiar with either analog or digital theory. The high gain and sensitivity of resonant antennas combined with the broad spectrum of a digital data-stream can easily make a novice more headaches than it is worth. Now obviously circuitry exists today that uses both technologies, just look at a cell phone. But a cell phone is designed by many engineering teams that have been formally taught EM theory and sound programming methodologies.

Thanks for answering me Del(and I must say I like your kickback to Maxwell, divergence and convergance, please excuse my spelling, I did not feel like spell checking)

1. Your first question, yes, I was looking for a simple I could use for switching, in answer to opinion, don't care if you think it is to much to start out with.

2. In answer to second question, a trap antenna, with each length shorted,insulated from the previous lengths, each tuned circuit at resonance, tuned and switched by the IC, preferably in a delta config(opposite of del symbol wise), just joking brother.

3. Three different frenquency spectrums, with the the IC doing the switching(through manual differentation).

4. In other words, I want to configure a trap antenna(see answer 2) in a delta config around the main radiating aperture and use the IC to control the radiating decision of shorted section of trap antenna.

thank you

and you redfred

If you are looking for a project, then perhaps you might want to try your hands at a light box. There should be some schematics on the web you can download. If you can't find one let me know and I'll copy one in for you. That would give you a project where the led outputs are frequency dependant.

Good Luck

I was looking at some of my own chips and found this Analog Devices chip. After investigating further on the ADI web page, I found this. You can get it here for $4.20 ea.

I'm not anything near an expert on these type of chips, but maybe redfred or another EE can help with application of it (but not Del, since he hates RF!).

I've used an earlier version of the ADG721 chips that are your first link. They will do precisely what the OP is looking for. Good find Mikerho.

I still stand by my comment that switching antenna circuitry is not a recommended project for a beginner. For an example the specification states that 2 pico-coulombs of charge injection will occur on every transition. This effect can in many applications be ignored. But in many high Q resonant circuits this can produce results that baffle many experienced electrical engineers.

But I must apologize to jrfloyd75. Antenna design and control is clearly your interest and passion to explore. I wish you the best in looking into this realm, but keep in mind that the switching noise of a microcontroller, digital clock pulse and the pseudo-random frequency spectrum of a serial data stream can wreak havoc with a static fixed antenna, let alone an agile antenna.

Getting back to the original question, the multiplex chip set ADG904 that Mikerho linked under "this" maybe a good choice for a diversity antenna application. I would start with allowing the user to select an antenna. For the next iteration I would consider trying to have some circuitry automatically choosing which antenna.