Reconfigurable Split-Pillar SIW Wire for Baseband and RF Broadband Communication on Chip

Fluctuating network traffic among IP blocks in multi-application Systems-on-Chips (SoCs) poses a significant challenge for designing energy-efficient interconnects, since energy efficiency in data transmission is highly dependent on both the traffic rate and the transmission mode. Broadband modes of transmission are efficient at high data rates but inefficient at low rates, while baseband modes exhibit the opposite behavior. To address the challenge of energy-efficient communication across varying traffic demands in SoC, this work proposes a reconfigurable Split-Pillar Substrate Integrated Waveguide (sp-SIW) that can operate in both baseband and Radio Frequency (RF) broadband mode of operation. The proposed sp-SIW, a variant of conventional SIW, incorporates optimized splits (0.25 mm) halfway through each metallic pillar at the side-walls of the waveguide, enabling low-frequency transmission down to Direct Current (DC). PIN diodes integrated within these splits facilitate switching between the dominant Transverse Electric (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$T$</tex> E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</inf>) mode for broadband signal propagation (above 20 GHz, similar to SIW) and the quasi- Transverse Electromagnetic (TEM) mode for baseband propagation (0 - 20 GHz, similar to microstrip lines). Results demonstrate that the sp-SIW, in baseband mode, exhibits superior signal integrity by suppressing crosstalk at baseband (<20 GHz) compared to microstrip lines. It also retains the strong suppression of crosstalk and radiation, similar to SIW, at broadband (> 20 GHz). The performance of the proposed sp-SIW was validated using Ansys High-Frequency Structure Simulator (HFSS).