The LCR is another type of resonator filter. A typical arrangement consists of two transducers in the space between two reflecting gratings. This is somewhat similar to the one-port resonator, Fig.1, but with two transducers. Using IDTs with strong internal reflections, the LCR can be designed to provide a filter with two high-Q poles. A typical configuration is shown in Fig.2. On a strong-coupling substrate such as lithium tantalate or niobate, this gives low insertion losses, e.g. 2 dB, at rf frequencies of 1 GHz and above. Bandwidths up to 5% can be obtained without the need for tuning components. The LCR can also be used on quartz substrates.