I saw the following antenna layout in a Texas Instruments application note titled AN043, Small Size 2.4 GHz PCB Antenna. What is with the right angle the feed makes? Wouldn't that cause reflections? Or is this a special impedance tuning technique (Kind of doubt that though).
Yes of course the 90 degree angle will cause reflections. Anything that isn't a proper transmission line of the right impedance will.
Question is, how much will it reflect and maybe it is low enough. Many times a design might not be perfect but that doesn't mean it's not good enough. I guess in this case the designers wanted flexibility so they placed some pads to place components. And this happened to be the result.