Your question seems to be contradictory -- you seem to be saying you want to "create a circuit" without actually "designing a circuit".
I'm going to interpret that as saying you want to "build a complete system, including designing a high-level protocol and laying out a few circuit boards and soldering integrated circuits to the boards and plugging sub-assembly modules into those boards", but you'd rather not "design and fab a full-custom ASIC from scratch" or "design something from dozens of discrete transistors instead of a chip" or "design and do EM simulations and construct a full-custom antenna system and get FCC approval".
I've heard that, at least for low data rates, that UWB can be produced using simple circuits using off-the-shelf chips that were common long before anyone ever heard of UWB.
Alas, I don't know any specific chips that you could use for the data rate you want, much less if there exist off-the-shelf modules using those chips, but I hear that such chips exist. Let me give you some links that might lead to those chips.
My understanding is that there is currently only one UWB standard --
WiMedia’s Multiband OFDM, standardized as ECMA-368 and ECMA-369.
My understanding is that "Certified wireless USB" and a potential future version of "Bluetooth" and a potential future version of "Zigbee" are higher-level layers on top of WiMedia's UWB standard.
My understanding is that there are several chip manufacturers producing chips that comply with this standard. a b
I hear that several other chip manufacturers are producing non-ECMA-compliant chips, including Pulse~LINK, DecaWave, IMEC, WiLinx, Wisair.
Presumably those chip use some other proposed standard or proprietary UWB techniques.
If you can't find an off-the-shelf module, and you find yourself looking for individual chips, I suspect that many of the chips developed for HomePlug might be usable as part of a UWB system.
You could use a FET bus switch, like the SN74CBT3125, however this will add about 5 ohms resistance in series with each capacitor. If that is a problem, you could always use reed relays like this one, each driven by a FET or BJT transistor, which would exactly emulate your current arrangement with the pushbuttons.
Best Answer
ICs as such dont have a shelf life, like milk or so. They do age on the shelf, though, but generally not as fast as when in use. What happens is you have a rising probability of ICs being dead when unpackaged, or dying earlier when used.
Oxidation, radiation (both natural and man-made), and chemical degradation of the dielectric, and probably several other aspects, degrade the ICs over time.
The effect of these influences largely depends on the manufacturing process and the quality of the IC. A well made IC may be less prone to oxidation, for instance. Older ICs (aka larger structures) have more material to be eaten away. Some ICs have dielectrics than can be more prone to aging. Modern ICs seem to be built with thinner, but more robust dielectrics.
All told, the ageing through technology means more. I do have perfectly working 74ls00 that is over 30 years old in an apparatus that is mostly turned off. Would I use it to build something today? Probably not.
But then again, from a museum perspective, it is quite important to know how to preserve ICs: Dry with a desiccant, in a metal container which is not radioactive seems to be the best bet.
See Aging of Integrated Circuits