CCITL implementation using two-section microstrip transmission lines

Conjugately characteristic impedance transmission lines (CCITLs), possessing conjugate characteristic impedances (Z₀^±) of wave propagating in opposite directions, are implemented using a terminated finite lossless reciprocal periodic structure consisting of a unit cell of 2-section microstrip reciprocal lossless transmission lines (TLs). Numerical simulations show the Z₀^± magnitudes of 50±0.24% Ω with their respective arguments φ^± varying nearly 30° over the frequency range of interest. The S₂₁ magnitude measured from the fabricated 2-section microstrip TL decreases more rapidly with the frequency, than that of the 4-section and reference 50 Ω TLs. It is found that the 2-section TL structure is easier to fabricate than the 4-section structure, with acceptable CCITL characteristics at the certain operating frequency.