21 channel SAW channelizer filter bank

The design and testing of a 21 channel SAW channelizer filter bank is described. In order to decrease the insertion loss, the individual filters used for the bank consist of a multistrip coupler and two apodized EWC-SPUDT. The experimental devices are fabricated on Y128° LiNbO₃, whose center frequencies are 251.25∼445 MHz with 6 dB bandwidth 8.5, 11, 15.5 MHz respectively, the insertion loss 9∼13 dB respectively, out-of-band rejection more than 40 dB and shape factor about 1.6. To reduce the insertion loss of input interconnection network, a modified and thus optimized series-parallel combination of the individual SAW filter is used. The experimental filter bank results in the bandwidth of 200 MHz, insertion loss of less than 19 dB, and stopband rejection of more than 40 dB.