 The wide @-@ band nature of waffle @-@ iron filters finds applications in satellite communications . A satellite earth station may have multiple diplexers connected to a multi @-@ band antenna feeder . Each diplexer delivers a wide @-@ band signal in a different band and it is essential that its signal does not contain out @-@ of @-@ band components , particularly harmonics . These can seriously interfere with , or even stop entirely , communication in another band . The diplexer must therefore have a stopband that is even wider than the passband . For this reason , as well as the other advantages of waffle @-@ irons , these diplexers are commonly made to a waffle @-@ iron design . 
