Quasi-Optical Transmission Loss Extraction for High-Frequency Stackup Design
Quasi-optical extraction isolates intrinsic substrate loss from copper roughness, requiring explicit z-axis anisotropy conversion for accurate mmWave stackup design.
sub-THz Interconnects
High Frequency Routing
Wideband signal routes enable the transmission of signals at frequencies ranging from 100 GHz to 300 GHz within advanced communication systems. Implementation of sub-thz interconnects requires radical departures from traditional board fabrication techniques due to the extremely short wavelengths of the signals. At these frequencies, even minute variations in trace geometry or dielectric properties cause measurable signal degradation.
Precision in etching and lamination becomes the defining factor for successful signal delivery.
Dielectric Selection
Materials with extremely low loss tangents and stable permittivity are necessary to maintain signal power. Many sub-thz interconnects utilize thin-film technologies or glass-based substrates to achieve the required dimensional stability. Minimizing the thickness of the substrate helps to suppress unwanted modes of propagation that would otherwise distort the waveform.
These materials must also resist moisture absorption to prevent fluctuations in electrical performance.
Interface Precision
Transition points between components and the board surface represent the primary challenge in the signal path. Because sub-thz interconnects are highly sensitive to parasitic capacitance and inductance, traditional wire bonding or large solder balls are often insufficient. Designers utilize specialized micro-vias and flip-chip bonding with tiny copper pillars to maintain a continuous impedance profile.
Laser-direct imaging and advanced plasma etching ensure that the trace edges are smooth enough to avoid scattering at the terahertz scale. Engineers verify the integrity of these paths using vector network analyzers equipped with frequency extenders.