Low-dispersion thin-film microstrip lines with cyclotene (benzocyclobutene) as dielectric medium

Abstract

We report on thin-film microstrip lines (TFMSLs) fabricated on low-resistivity Si with polymerized cyclotene as the dielectric between signal and ground conductor, all on top of the wafer. Electro-optic high-frequency characterization of the TFMSLs reveals negligible modal dispersion up to the highest frequencies of 1.0 THz. In spite of the high substrate conductivity, the attenuation is low (⩽1 dB/mm at 100 GHz). Over the full frequency range, it is dominated by conductor losses and not by absorption in the dielectric. With these dispersion and attenuation properties, TFMSLs are an attractive alternative to coplanar waveguides, with the additional advantage of immunity against substrate absorption and radiation losses.

Coherent and ultrafast optoelectronics in III–V semiconductor compounds

“…10(d). Frequency-domain propagation parameters (not shown here) of the wire have been retrieved from the time-domain data by a procedure described in [55]. Using these freely-positionable PC probetips the frequency-dependent attenuation and dispersion behaviour of Sommerfeld wires was measured in qualitative and quantitative agreement with numerical field simulations [64].…”

“…7 have been used for the fabrication of integrated PC switches on host substrates. The first two concepts differ by the order of the process steps of LT-GaAs transfer and metal electrode (planar waveguide) structuring on the HS [53,55]. In a third alternative, the electrode structures are defined on the LT-GaAs chip before it is transferred to the HS.…”

“…The first example of bonded LT-GaAs chips used for integrated PC switches we want to discuss, is focused on the excitation of THz pulses on thin-film microstriplines (TFMSLs) with the low-k polymer benzocylobutene (BCB) as dielectric [55]. As sketched in Fig.…”

Optoelectronic characterization of transmission lines and waveguides by terahertz time-domain spectroscopy

“…The Cherenkov radiation loss was eliminated by the use of silicon-on-insulator materials with a microstrip geometry [32] and thin-film microstrip lines [33], but the total observed loss owing to the dielectric and the metal was still approximately the same as that for the coplanar transmission line. A variety of transmission line structures have been designed to reduce the permittivity mismatch responsible for the Cherenkov radiation [34]- [37].…”

THz wave propagation on strip lines: Devices, properties, and applications

“…Though a silica-based membrane was presented in the previous work [8], it is not simple in fabrication and not very robust mechanically. On the other hand, in 1997, a low loss and small dispersion propagation was reported using the MSLs with 10 μm-thickness dielectric layer based on low permittivity polymer materials [9]. It was also demonstrated that the MSLs can be used as a sensitive label-free detector of DNA molecules, by using a resonator structure in the MSL, though the spectral range of the devices was still in sub-THz range [10].…”