A Computer‐controlled System of Transmission Lines for the Determination of the Complex Permittivity of Lossy Liquids between 8.5 and 90 GHz

A system of computer controlled transmission lines based on the method of travelling waves is presented, permitting the precise determination of complex permittivities of medium to high loss liquids at 8.5 to 90 GHz. It consists of a newly developed apparatus for the E‐band region (60 ≤ v /GHz ≤ 90), which is described in detail, together with existing X‐ (8.5 ≤ v /GHz ≤ 12.4), Ku‐ (12.4 ≤ v /GHz ≤ 18), and A‐band (26.4 ≤ v /GHz ≤ 40) set‐ups now appropriately adapted for computer control. Consistency and accuracy of the equipment are evidenced with the help of permittivity data for water, methanol, N‐methylformamide (NMF), and N,N‐dimethylformamide (DMF).