User's Manual

LE940B6 Hardware User Guide
1VV0301331 Rev. 1.8 - 2017-03-15
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The interface board is realized on a FR4, 4-layers PCB. Substrate material is characterized by
relative permittivity εr = 4.6 ± 0.4 @ 1 GHz, TanD= 0.019 ÷ 0.026 @ 1 GHz.
A characteristic impedance of nearly 50 Ω is achieved using trace width = 1.1 mm, clearance from
coplanar ground plane = 0.3 mm each side. The line uses reference ground plane on layer 3, while
copper is removed from layer 2 underneath the line. Height of trace above ground plane is 1.335
mm. Calculated characteristic impedance is 51.6 Ω, estimated line loss is less than 0.1 dB. The line
geometry is shown below:
7.5.2. Transmission line measurements
E5071C NA (Full-4-port calibration) has been used in this measurement session. A calibrated
coaxial cable has been soldered at the pad corresponding to RF output; a SMA connector has
been soldered to the board in order to characterize the losses of the transmission line including
the connector itself. During Return Loss / impedance measurements, the transmission line has
been terminated to 50 Ω load.
Return Loss plot of line under test is shown below: