System Integration and Packaging of a Terahertz Photodetector at $W$ -Band

Abstract

This paper presents the system integration and packaging of a photodetector at W-band (75-110 GHz) for terahertz (THz) communications. The ErAs:In(Al)GaAs photoconductor and its feeding network based on semi-insulating indium phosphide (InP) substrate are introduced. The design of the bias-tee at W-band is described and the effect of parasitic modes is discussed. Besides, the transition using E-plane probe between a W-band rectangular waveguide (WR-10) and a coplanar waveguide (CPW) is illustrated. The bias-tee as well as the E-plane probe transition are based on high-resistivity silicon (Si) substrate where wire bonding bridges are added on the top following the CPWs in order to restrict parasitic modes. The integration approach and the packaging structure are addressed. The proposed bias-tee and the E-plane probe transition including the WR-10 rectangular waveguide are fabricated, integrated, and measured. The measurement is carried out on-wafer in a back-to-back configuration and the results are presented. The assembly of the fully-packaged photodetector is demonstrated and a THz heterodyne communication system is implemented which validates the proposed system integration and packaging approach of the photodetector at W-band.

Highly Tunable Heterodyne Sub-THz Wireless Link Entirely Based on Optoelectronics

“…This device is originally designed for spectroscopy applications in which signals with frequencies in the order of kHz are detected, and not to support IFs above 1 MHz. However, the same devices can be designed without these limitations, so they become suitable for broadband communications [19].…”

“…Some works have already attempted to establish heterodyne wireless links driven by optoelectronic techniques, covering a wide range in the sub-THz domain [19]. The first realizations of communication links using optoelectronics at both sides have been recently reported [20], [21].…”

Broadband flip‐suspended‐microstrip transition for millimeter‐wave MMIC package

“…Another solution is integrating probes with monolithic circuits. [12][13][14] Although there is no need of any additional wires or bumps, the MMICs are usually large in width and easily cause undesired mode excitations. Moreover, the performance evaluation of the on-chip MMIC for post-packaging is unavailable.…”

“…However, this structure must be designed in combination with the complex fabrication process and shielded line systems to avoid radiation. Another solution is integrating probes with monolithic circuits 12–14 . Although there is no need of any additional wires or bumps, the MMICs are usually large in width and easily cause undesired mode excitations.…”