Other Parts Discussed in Thread: CC2530
Is it a sin to route the Inverted-F antenna on the opposite side of the PCB from the CC2592? A Faraday cage will cover the CC2530 and the CC2592, but mechanical constraints yearn for the inverted-F to be on the opposite side of the board. The order of layers (4-layer PCB) will be reversed vis-a-vis the T.I. app note (ground plane 2nd under the antenna).
1) How to maintain a 50-ohm impedance path through the via? Is this significant or unimportant? Does the diameter of the via, the thickness of the copper down the via, or other geometric aspects have to be addressed separately?
2) Which devices should, ideally, be placed within the Faraday cage? For example, is it advantageous or otherwise to include an external RAM component or I/O expander within the cage, or should only the CC2592, or the combination of the CC2592 and CC2530 be placed within the cage? Should the Balun or discrete filter components be placed inside the cage or outside? (I assume inside).
3) Will impedance mismatch at zero-Ohm resistor jumpers lead to power loss (transfer) alone, or can these interfaces result in harmonic generation? What about a curved 50-trace to the antenna?
4) Now, here is the interesting/Poltergeist - a large harmonic is generated at half-primary (1.2GHz). Can't tell about multiples because my analyzer only goes to 3.2 GHz. When placing my finger over a zero-Ohm jumper in the antenna trace I can make the 1.2GHz energy go away. This implies that a capacitor might redirect this half-harmonic energy to ground. Does this makes sense?
JS
