What frequency range and what power level??
What kind of power allowance do you have?
Is port isolation necessary?
around 0 - 30dB input range, not that much. how isolation is important? since they are splitted into same signal. i guess not really important.
Or if the PCB distances are very short WRT to the wavelength (< 1/8 lambda) then just terminate it at the PCB ingress point. Or maybe the split point.
this is what i want to hear but... maybe i just tried to reinvent the wrong wheel. the 1st rf man in the universe probably tried this before and found out its a wrong idea if traces start to get too long.
one application i can think of is each arm will be input for adc, 2,3,4 etc arms = 2,3,4 etc adc, each adc will read input (same input on each arm) at slightly different time (interleaved) for higher sampling rate. say if we want to achieve 2GSps sample rate, maybe we can use 10 200MSps adc's, cheap!
so we'll need 10 ways splitter, just thinking