Ideally, the impedance of PCB traces should be matched to the load and source impedances. This becomes especially important in high-frequency and high-speed digital PCB designs. Various rules of thumb are available to determine the critical length at which a PCB trace should be treated as a transmission line. Below this critical length, an impedance mismatch can safely be ignored. Or can it?
This article shows how to modify an inexpensive LNB to accept an external LO-reference signal in order to be used as a K-band downconverter for QO-100 (Qatar Es’hail 2) amateur radio sattelite reception, radio astronomy or similar K-band experiments.
This article will show how to design a 2-way equal split lumped-element Wilkinson power divider with 50 Ω impedance for 28 MHz. Lots of big words; reread just to make sure you read it correctly and you don’t have to read through this article just to realize it’s not what you need. The Wilkinson works both as splitter and combiner.