An electrically interconnected, linear array of photodetectors is a useful component for several optoelectronic systems applications. Traveling-wave concepts were employed in matching arrays of metal-semiconductor- metal photodetectors to a 50 (Omega) load, over a broad bandwidth. The photodetectors are embedded in a microstrip transmission line, to form a periodically loaded structure. The bias of each detector is independently controllable. Such periodic structures can be designed to exhibit specified characteristic impedance, and to be non-dispersive up to very high frequencies. With proper matching, each photodetector exhibits broadband response into an external load. Experimentally, a monolithic array of eight metal- semiconductor-metal photodetectors, attached to a microstrip bus, is shown to have uniform 12 GHz bandwidth. A model for the array is discussed, and theoretical and experimental results are in good agreement. Applications of broadband photodetector arrays are also discussed.