In a passive surface wave sensor for measured value determination, a measured value is transmitted by radio from a remote measuring location to an interrogation device, which transmits energy by radio to a sensor element as an interrogation pulse. The surface wave sensor is suitable for contactless measured value acquisition. A surface wave configuration is the sensor element and a surface wave reference element is provided for phase discrimination and/or propagation time measurement. As a further development, a sensor operated with chirped transmitting signals and having chirped reflectors is provided, in which the configuration has a reference function in place of the reference element. A sensor constructed in such a way that it has a chirped function has the characteristics of an imminently temperature-compensated sensor for measuring other physical or similar variables.