Yes, the components are absolutely necessary (for that antenna design geometry) to transfer power from a source designed to produce X power into X resistive impedance. The LC (that can be electronic components or the equivalent physical values from conductors) matching network is much like a tuned transformer that optimizes power transfer from one set of driving impedance combinations (source to antenna) to another impedance combination called free-space and back again in receive mode. The antenna is designed to phase shift the fields generated across the conductors in respect to existing fields moving away that were previously generated across the antenna. The limited speed of 'light' means changing RF field effects happen at different times across space. At some size, length and shape (antenna geometry) of the electrical (modified by LC components if necessary) length of conductors RF power is matched to space and that RF power moves into space. The transfer of power from the antenna to space is seen as resistive by the power source so a closer resistive impedance match means more power transfer.After much experimenting, I'm about to finally install the module on one of my circuits so that a PIC16 will be able to interact with it. But now I've run into a conundrum... one of the module's pins (pin #2) is intended so that an antenna can be connected to it. I've been playing around with an evaluation board of said module, and I noticed that the antenna's connection is not as straightforward as one might think. In fact, after some measurements and verification, I found that the antenna is connected in series to what seems to be a ferrite (a small inductor whose resistance is about 0.015Ω), and also to a capacitor (1nF) connected to ground. Here's a couple of pictures, plus a diagram of the way I understand the antenna is connected to the module:
So I have three questions:
- Are said components absolutely necessary? Or are they more of a recommendation to filter and refine reception/transmission?
- Should the geometry of the antenna I plan to use be similar to the one present in the evaluation board?
- Is the length of the antenna important?
Here's a clip from the datasheet that might be pertinent to my questions:
@nsaspook, this sort of thing seems to be right up your alley, any thoughts? @joeyd999 awhile ago I followed one of your threads in which you documented your progress with a Bluetooth module, maybe you'll find this thread to be of your interest.