My main background is embedded software but I have had to debug the analog circuitry myself so I've picked up a little bit here and there, enough so to describe the problem in a coherent way to someone who could give me a solution. At my work, I was on a project where we were developing a hand-held radar transceiver that operated in the single Ghz frequency range. One particularly thorny issue that we never resolved was the antenna connectors we used introduced ringing artifacts in the receive signal. To prove this as a source we would put 50ohm terminators instead of the antennas and would observe a significant decrease in the noise in the signal. We also observed decreasing noise as we introduced progressively longer lengths of cable between the Tx/Rx connector and their respective antennas. So the initial conclusion was to introduce delay between the connectors and their antennas to dissipate the ringing and make our lives easier on the Rx side.
So the real problem is how do we implement that delay, preferable 15-20ns worth, where space is our main constraint (the last board we built was two dual-side 10cm x 10cm boards, one for the electronics and the other for the antennas with the aforementioned connectors between the two boards)? I had once suggested drawing out trace paths between the connectors and antennas in the same manner as illustrated in this question except that's for digital signals and my limited experience with analog signals has taught me that analog RF signals are a lot more pickier than digital signals. Never did get to try out my idea and now the project is on hold for lack of funding.
So if nothing else I'd like an answer to whether using PCB traces for large analog RF delay is a feasible idea and what pitfalls would need to be considered. Is this even a common practice or does the RF world rely on special circuits to do that function? Another project which I was involved in had the same problem and used a gated switch as a solution which worked but added quite a bit more components (guesstimate of 25% extra space required). I'm mostly looking for a general argument about how this problem could be approached but references would also be appreciated (even if its way above my head!). Thanks.