Compact 100GHz to 300GHz on-chip triplexer in SiGe HBT technique for subTHz channelization applications

An on-chip triplexer is proposed to provide three passbands: Band1 95 GHz to 115 GHz, Band2 196 GHz to 215 GHz, Band3 292 GHz to 317 GHz to cover 100GHz, 200GHz and 300GHz. The design achieves good compactness with dimensions of 0.79 mm × 0.64 mm (0.26×0.21 λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>, where λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> is the free-space wavelength at 100 GHz) by employing open-ring stepped-impedance resonator (SIR) filters and folded lines. To further reduce the chip layout, a dual-band filter replaces the conventional two single-bandpass filters in the triplexer design. The channels, with bandwidths exceeding 10 GHz, exhibit out-of-band rejection greater than 20 dB. The triplexer was implemented based on the redistribution layer (RDL) of SiGe HBT technology. Measurements were conducted to validate the design, and key material properties: dielectric constant (Dk), loss tangent (Df), and surface roughness were optimized and incorporated into the simulations. A good agreement between measured and simulated results confirms the effectiveness of the design.