 Waffle @-@ iron filters are particularly suitable where both a wide passband , and a wide stopband free of spurious transmission modes , are required . They also have a high power @-@ handling capability . Applications include suppressing the harmonic output of transmitters and the design of wide @-@ band diplexers . They are also used in industrial microwave manufacturing processes to prevent the escape of microwave radiation from the microwave chamber . Filters with an analogous design are now appearing in photonics , but , due to the higher frequency , at a much smaller scale . This small size allows them to be incorporated into integrated circuits . 
