Apparatus and method for impedance balancing of long radio frequency (RF) via

A tangible and non-transitory computer readable medium having program instructions which when executed by one or more processors causes the one or more processors to:

• model a radio frequency (RF) via having a via hole formed in a plurality of printed circuit board (PCB) layers (L3-L19), the via hole having a center conductive support column, a primary longitudinal structure (221) comprising a constant longitudinal structure (227), a first principal tuning sub-assembly (229A) formed in a first portion of the RF via (220) located above the constant longitudinal structure (227) and at a first or entrance end of the primary longitudinal structure (221) and comprising a first set of pad, anti-pad pairs (445, 545, 645) to receive and pass an RF band, and a second principal tuning sub-assembly (229B) formed in a second portion of the RF via (220) below the constant longitudinal structure (227) and at a second or exit end of the primary longitudinal structure (221) and comprising a second set of pad, anti-pad pairs (445, 545, 645) tuned to receive and pass the RF band and mirroring the first set of pad, anti-pad pairs (445, 545, 645);
• tune the model by independently changing radii of one or more pad, anti-pad pairs of the first set of pad, anti-pad pairs (445, 545, 645);
• tune the model by mirroring the changes to the radii in the first set of pad, anti-pad pairs in the second set of pad, anti-pad pairs (445, 545, 645);
• determine whether the tuned first set of pad, anti-pad pairs (445, 545, 645) and the tuned second set of pad, anti-pad pairs (445, 545, 645) are symmetrically tuned to the RF band;
• and
• repeat the tuning of the model using the first set of pad, anti-pad pairs (445, 545, 645) and the second set of pad, anti-pad pairs (445, 545, 645) until a level of tuning is achieved.

A method comprising:

• modelling a radio frequency (RF) via having a via hole formed in a plurality of printed circuit board (PCB) layers (L3-L19), the via hole having a center conductive support column, a primary longitudinal structure (221) comprising a constant longitudinal structure (227), a first principal tuning sub-assembly (229A) formed in a first portion of the RF via (220) located above the constant longitudinal structure (227) and at a first or entrance end of the primary longitudinal structure (221) and comprising a first set of pad, anti-pad pairs (445, 545, 645) to receive and pass an RF band, and a second principal tuning sub-assembly (229B) formed in a second portion of the RF via (220) below the constant longitudinal structure (227) and at a second or exit end of the primary longitudinal structure (221) and comprising a second set of pad, anti-pad pairs (445, 545, 645) tuned to receive and pass the RF band and mirroring the first set of pad, anti-pad pairs;
• tuning the RF via (220) by independently changing radii of one or more pad, anti-pad pairs of the first set of pad, anti-pad pairs (445, 545, 645);
• tuning the RF via (220) by mirroring the changes to the radii in the first set of pad, anti-pad pairs in the second set of pad, anti-pad pairs (445, 545, 645);
• determining whether the tuned first set of pad, anti-pad pairs (445, 545, 645) and the tuned second set of pad, anti-pad pairs (445, 545, 645) are symmetrically tuned to the RF band;
• and
• repeating the tuning of the RF via (220) using the first set of pad, anti-pad pairs (445, 545, 645) and the second set of pad, anti-pad pairs (445, 545, 645) until a level of tuning is achieved.