Seahee Hwangbo

Through Glass Via (TGV) disc loaded monopole antennas for millimeter-wave wireless interposer communication

A monopole antenna loaded with a circular disc is integrated on a glass interposer layer for millimeter-wave wireless communication applications. A Through Glass Via (TGV) is used as a main radiator and the circular disc is for a impedance matching. An omnidirectional radiation pattern formed by the monopole antenna allows in-plane wireless communication whose distance is much larger than 1cm. This can solve problems such as cross talk and time delay caused by the conventional wire bonding approach. A 77 GHz (W-band) antenna is designed and fabricated as a prototype on a glass substrate. The simulated peak gain of the antenna is 1.23 dBi. Also, as this antenna concept is scalable, the same architecture has been exercised for a 5.8 GHz industrial, scientific and medical, ISM band application. The design, fabrication, and characterization are detailed. The measured results of the return loss and radiation pattern agree well with the simulation results.

Glass interposer integrated dual-band millimeter wave TGV antenna for inter-/intra chip and board communications

A dual-band and dual-mode millimeter wave through glass via (TGV) antenna integrated in a glass interposer layer has been designed for wireless inter-/intra chip and board communications. A disc loaded TGV antenna is configured as a directional patch mode for out-of-plane communications at 62 GHz (WiGig), where the disc is a main radiating element, while the antenna operates as an omni-directional monopole mode for in-plane communications at 77 GHz (W-band), where the vertical via is a main radiating element. As the glass interposer layer serves as an antenna hosting material as well as an electromagnetic wave channel medium for wireless communications, low dielectric loss glass substrates with a loss tangent of 0.0036 are adopted.

Millimeter-Wave Wireless Intra-/Inter Chip Communications in 3D Integrated Circuits Using Through Glass Via (TGV) Disc-Loaded Patch Antennas

A Through Glass Via (TGV) disc-loaded patch antenna is integrated in a glass interposer layer for millimeter-wave intra-/inter chip wireless communication applications in W-band (75GHz -- 110GHz). The circular disc on the bottom side is utilized as a main radiator (patch antenna) and the TGV is for a vertical feeding line connected to the coplanar waveguide (CPW) on the top side of the glass substrate. A broadside radiation pattern formed by the circular patch antenna enables out-of-plane wireless communications whose distance would be a few mm to a few cm. By using such a wireless interconnect approach, problems such as cross talk and time delay associated with the conventional wired interconnects could be reduced. A TGV fed patch antenna is designed and fabricated, which shows a return loss of 20.88 dB at 84.8 GHz, a 10 dB bandwidth of 31.3 % (80.39 GHz to 107.06 GHz). The measured results are matched well with the simulation ones. The simulated peak gain of the antenna is 3.14 dBi.

Cu/Co metaconductor based high signal integrity transmission lines for millimeter wave applications

This work reports copper/cobalt (Cu/Co) metaconductor based coplanar waveguide (CPW) transmission lines, featuring excellent signal integrity at K-bands and millimeter wave frequencies such as low conductor loss, reduced signal dispersion, and low noise figure. CPW transmission lines consisting of 10 pairs of Cu/Co thin film metaconductors with each layer thickness of 150 nm/25 nm, respectively, have been designed, fabricated and characterized. Experimental results show an RF resistance reduction of up to 50 % (Max.) in 7 GHz–32 GHz, 25.5 % delay performance improvement, and 30 % thermal noise voltage reduction compared with reference copper based CPWs. Compared with devices from other literatures, the presented device shows the best signal integrity performance in Ku, K, and Ka bands.

Fabrication and Characterization of Nanoporous Metallic Interconnects Using Electrospun Nanofiber Template and Electrochemical Deposition

In this work, a nanocomposite interconnect consisting of ferromagnetic and non-ferromagnetic materials is theoretically and experimentally investigated. The relative magnetic permeability of ferromagnetic nanofibers becomes negative above the ferromagnetic resonance frequency and induces eddy current in an opposite direction of that of non-ferromagnetic conductor, resulting in eddy current cancellation. This ultimately suppresses the skin effect contributing to the reduction of radio frequency resistance. For nanofiber fabrication, an alternating electrospinning technique is utilized to improve the nanofiber growth rate and increase the thickness of the nanofiber stack. Aligned nanofibers are obtained by dynamically rotating mandrel combined with alternating electrospinning. Nanoporous conductors with the composition of non-ferromagnetic and ferromagnetic conductors are realized by electrochemical deposition of copper with the ferromagnetic nanofiber stack as a plating template.

Directional through Glass Via (TGV) Antennas for Wireless Point-to-Point Interconnects in 3D Integration and Packaging

A directional Through Glass Via (TGV) antenna is designed in a glass interposer layer for W-band (75GHz – 110GHz) wireless point-to-point chip communications with a center frequency of 78 GHz. The TGV is utilized as a main radiator (monopole antenna), which is fed by the coplanar waveguide (CPW) on the top side of the glass substrate, a circular disc is loaded on the tip of the TGV for input impedance matching, and an array of TGV reflectors are placed in proximity along with the perimeter of the circular disc in one side of the monopole antenna, forming a directional radiation pattern in the opposite direction of the reflectors. The directional radiation pattern enables not only to realize point-to-point lateral wireless communications with a distance of up to a few cm in 3D System-in-Packaging (SiP), but also to serve as an electromagnetic shield, preventing the EM signals from being transmitted towards the unwanted directions. With the wireless interconnect approach, enhanced signal integrity over far distance data transmission is expected such as low latency and low cross talk. A test antenna is designed and fabricated on the glass substrate, and a return loss of 21.6 dB at 78 GHz and a 10 dB bandwidth of 16.6 % (70.75 GHz to 83.67 GHz) have been achieved. The measured and simulated radiation frequencies are matched well. The simulated front-to-back ratio and gain of the antenna is 2.3 dBi and 20.3 dB, respectively.

Glass interposer integrated millimeter wave antennas for inter-/intra chip communications

Millimeter wave antennas are integrated in the glass interposer layer for wireless inter-/intra chip/board communications. For in-plane communication, a disc loaded monopole antenna with an omni-directional radiation pattern is designed while for out-of plane communication, a similar architecture with patch mode radiation is configured. These antennas are useful for wireless interconnects in three dimensional integrated systems in package.