Abstract: An N.times.M signal routing matrix has low loss. The N input ports are connected to N input transmission lines, and the M output ports are connected to M output transmission lines. A plurality of interconnects interconnect the input and output transmission lines at their crossing points. The points of connection of the interconnects to any one of the input or output transmission lines are spaced .lambda./2 (or multiples thereof) apart along the transmission line. Each interconnect includes a transmission line at least .lambda./2 long, and each includes a short-circuiting switch arrangement capable of short-circuiting the inteconnecting transmission line at point(s) .lambda./4 (or odd multiples thereof) from the ends of the interconnecting transmission line.