Miic.u. ixni-CT.ixtii i.\ ii-.iri iiliiks km 



Its .itu-nii.ilioii cli.ir.u-liTistir (Nd. I") ul I'ij^. J I) j?, imiqin- as .1 low- 

 pass ihariuloristir in iliat the iittetinatioti cotislaiit is finite at all fre- 

 quencies. Till' phasf rharartrrislir siinul.iti-s, in a gcnoral wa>', that 

 of till" two I'IciiK'nt low pass tiitor (si-v propagation cliararlrristif 

 No. 1 of l-'ig. 7) l>iit llu> phase shift in the transmission Ihind is, in 

 geni-ral, dilTi-ri'iit. Sinro thi- structure has niid-scrii-s iinaRi- ini- 

 (K'danco rharactoristir .No. 1 it may l)e joinwl ollficiently (i.i-., without 

 ri'lK'ction It)sses) to sections of the 1 — 2 and I —15 i\ pes. 



Similarly, high pass protot>pe section 4'— 1 has a uni(|Ue hijj;h pass 

 attenuation characteristic in that the attenuation constant is finite 

 at all fretiueiicies. The phase characteristic is, in general, similar 

 to that of the two element hit;h pass filter 2— 1 except for the \alues 

 of the phase constant in the transmission hand. The section may lie 

 joineil etViciently at mid-shunt to sections of the 2—1 and 4—1 tyjies — 

 since it has the same mid-shunt image characteristic (No. 9). 



The attenuation characteristics of the band pass prototypes listed 

 in Table III will, in general, differ from the attenuation character- 

 istics of structure listetl in Table II. However, many of them differ 

 only in minor res[x?cts and could ha\-e been represented identically 

 in the sNiiibolic fashion of Fig. 7. Inasmuch as such structures will 

 not, howe\er, have exactly the same attenuation characteristics for 

 given cut-ofT frequencies and frequencies of infinite attenuation, 

 difTerent symbols or diagrams have been em()Ioyed to represent them. 



Certain characteristics are worthy of comment because they are 

 not obtainable, even approximately, in structures not having negative 

 inductance. For example, propagation characteristics Nos. 1(5 and 26 

 (Fig. 44) arc band pass filter characteristics having finite attenuation 

 at all frequencies. Characteristics No. 22 and No. 2i) are unique in 

 that there exist two frequencies of infinite attenuation, located on 

 one side of the pass band. The attenuation constant is, in general, 

 finite at zero and at infinite fretiucncies. Charat'tcristics 19 and 28 

 are special cases of Nos. 22 and 29, respectively, and have two fre- 

 quencies of infinite attenuatif>n on one side of the pass band. In 

 the case of 19, the attenuation is infinite at zero frequency and at a 

 frequency between zero and the lower cut-otT freciuency. Charac- 

 teristic 28 has infinite attenuation at infinite frequency and also at a 

 fretjuency between the upper cut-ofT frequency and infinite frequency. 

 Characteristics Nos. 18 and 27 have confluent band characteristics 

 and have onl\- one frequency of infinite attenuation, located either 

 at zero frequency or at infinite frequency. Finally, characteristics 

 Nos. 20 and 31 are confluent characteristics in each of which one fre- 



