Line Parameters in the Extreme Case

If has been already proved fhaf line paramefers af an infinife frequency are fhe same as fhose in fhe perfecfly conducfing earfh and conductor case. If is quite useful to know fhe line paramefers in such fhe exfreme case, because fhe paramefers are a good approximafion to fhe line paramefers af a finite frequency wifh imperfecfly conducfing earfh and conductor. 

From fhe sfudy in fhe previous secfions, fhe following paramefers have been known af fhe infinife frequency or in fhe perfecfly conducfing media case. 

From the previously mentioned impedance and admittance, we can derive the following line paramefers in fhe acfual phase domain. 

From the earlier results, it is clear that the product Z Y or the actual propagation constant matrix is diagonal and purely imaginary at the infinite frequency or in the perfect conductor case. This results in the fact that the attenuation is zero and the propagation velocity is a light velocity in free space on any phases. Also, it is noteworthy that the modal theory is not necessary as far as only the propagation constant is concerned, because it is already diagonal. 

It is clear that the actual characteristic impedance is constant independently of frequency. 

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