When {HEAD ~ a splitting structure} is arranged based on {TAIL ~ the symmetrical splitting structure}, a straight waveguide may be connected to a Y type waveguide element, especially at the input waveguide, which means that a waveguide extending to the outermost output port partially includes a straight waveguide, thus causing the waveguide to become longer 
When { HEAD ~ a splitting structure } is arranged based on { TAIL ~ the symmetrical splitting structure } , a straight waveguide may be connected to a Y type waveguide element , especially at the input waveguide , which means that a waveguide extending to the outermost output port partially includes a straight waveguide , thus causing the waveguide to become longer
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH