Low-loss, low-cost and mass-manufacturable PCB with embedded chip and waveguides paves the way for next-gen D-Band applications

LEUVEN (Belgium), JUNE 12, 2023 — At this week’s International Microwave Symposium, imec – a world-leading research and innovation hub in nanoelectronics and digital technologies, and AT&S – a leading manufacturer of high-end printed circuit boards (PCBs) and IC substrates, present a major step towards realizing a novel system integration approach, whereby D-Band chips and waveguides are integrated into low-cost, mass-manufacturable PCBs. This new approach paves the way for the development of compact, cost-effective, and high-performance 140 GHz (automotive) radar and 6G mobile communications systems, offering significantly lower signal loss in comparison to planar PCB lines or substrate-integrated waveguides (SIWs) in PCBs and interposers.

The need for higher bandwidths in applications such as automotive radar and upcoming 6G mobile networks is fueling the demand for higher radio frequencies. This is why the D-Band, spanning from 110 to 170 GHz, garners significant attention.

But tapping into these frequencies poses challenges, such as increased system complexity and signal attenuation. Hollow air-filled substrate-integrated waveguide (AFSIW) technology with fully metalized sidewalls offers significantly reduced signal loss compared to substrate-integrated waveguides (SIWs) that use rows of vias and the planar interconnect technology used in current communication and radar systems. Despite this intrinsic benefit, a mass-production approach for PCBs with integrated AFSIW waveguides is currently unavailable.

The world's first implementation of D-Band AFSIWs in a low-cost, mass-manufacturable PCB – coming with a five-fold loss reduction

“To facilitate the next generation of cost-effective, high-performance radar and communication systems, millimeter-wave front-end systems that can operate at frequencies exceeding 100 GHz are necessary. However, a key concern is how these antennas and millimeter-wave ICs can be optimally connected. We believe a key part of the solution is to utilize AFSIW technology. Unfortunately, such waveguides are expensive and hard to integrate into multi-layer PCBs or interposers. Imec and AT&S have partnered to address this challenge. Together we demonstrate an integrated front-end combining imec’s 140 GHz radar ICs in combination with a novel packaging/module concept developed by AT&S. The demonstration of PCB-integrated AFSIWs is an important breakthrough towards achieving this end goal,” said Ilja Ocket, program manager at imec.

3D model and EM field plot of a compact stripline-to-AFSIW transition.

As part of an advanced system module concept, AT&S and imec have collaborated to develop D-Band AFSIWs with solid copper sidewalls integrated into a multi-layer PCB to prevent signal leakage and to form arbitrarily shaped air cavities. It is the first successful demonstration of an AFSIW operating above 100 GHz, and integrated into a low-cost, mass-manufacturable PCB. By eliminating dielectric losses, so that only conductor losses remain, the new approach achieves a loss of 0.07 to 0.08dB/mm across the 115 to 155 GHz frequency range, translating into a five-fold reduction compared to reported planar PCB lines or SIWs in PCBs and interposers. These impressive results only represent a first step, as further improvements will continue to drive down losses even further in the coming years.

From enhanced awareness in automotive to 6G networks

“Imec’s 140 GHz radar chips and packaging design expertise have given us a significant head start. We believe that our new packaging approach can be utilized to create efficient, compact, and high-resolution 140 GHz radar modules for automotive applications, creating vehicles that are increasingly ‘aware’ of what is happening, both in-cabin and around them,” said Erich Schlaffer, program manager R&D Electronics Solution at AT&S. “Additionally, this technology will find its way in 6G mobile networks.”

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About imec

Imec is a world-leading research and innovation center in nanoelectronics and digital technologies. Imec leverages its state-of-the-art R&D infrastructure and its team of more than 5,500 employees and top researchers for R&D in advanced semiconductor and system scaling, silicon photonics, artificial intelligence, beyond 5G communications and sensing technologies, and in application domains such as health and life sciences, mobility, industry 4.0, agrofood, smart cities, sustainable energy, education, … Imec unites world-industry leaders across the semiconductor value chain, Flanders-based and international tech, pharma, medical and ICT companies, start-ups, and academia and knowledge centers. Imec is headquartered in Leuven (Belgium), and has research sites across Belgium, the Netherlands, and the USA, and representation in three continents. In 2022, imec's revenue (P&L) totaled 846 million euro.

Further information on imec can be found at www.imec-int.com.

Imec is a registered trademark for the activities of imec International (IMEC International, a legal entity set up under Belgian law as a “stichting van openbaar nut”), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland),  imec Taiwan (IMEC Taiwan Co.), imec China (IMEC Microelectronics (Shanghai) Co. Ltd.), imec India (IMEC India Private Limited), imec San Francisco (IMEC Inc.) and imec Florida (IMEC USA Nanoelectronics Design Center Inc.).

Contact: Jade Liu, international press officer // T +32 16 28 16 93 // M +32 495 71 74 52 // Email Contact

About AT&S

AT&S (AT&S Austria Technologie & Systemtechnik Aktiengesellschaft) is a globally leading manufacturer of high-end printed circuit boards and IC substrates. AT&S industrialises leading-edge technologies for its core business segments Mobile Devices & Substrates, Automotive, Industrial and Medical. AT&S has a global presence with production sites in Austria (Leoben, Fehring) and plants in India (Nanjangud), China (Shanghai, Chongqing) and Korea (Ansan near Seoul). A new high-end production site for IC substrates is currently being established in Kulim, Malaysia. And in Leoben, a unique European competence centre with connected series production for IC substrate technologies is being built right now. The company employs about 15,000 people. For further information please visit  www.ats.net