After all, radiowaves, microwaves, and visible light are all electromagnetic radiation; they differ only in frequency. So other things equal, a microwave circuit shrunk down by a factor of 100,000 will behave the same way but at 100,000 times higher frequency.
Radio waves, microwaves, and visible light are all forms of electromagnetic radiation; they differ only in their frequency. A smaller microwave circuit, shrunk by a factor of 100,000, would behave similarly but at a frequency that is 100,000 times higher.