Design and Analysis of LTCC-Integrated Planar Microstrip-to-waveguide Transitin at 300 GHz

A 300-GHz planar microstrip-to-waveguide transition in low-temperature co-fired ceramic (LTCC) is numerically and experimentally analyzed. A via fence and air holes are used to form a three-dimensional transition structure and a vertical hollow waveguide inside the multilayer LTCC substrate. The transition consists of a coplanar-waveguide-fed slot radiator backed by a short-wall of the waveguide and an open-circuited microstrip resonator. On the basis of the dual operation mechanism, the design guideline for the complex 3D structure is described using full wave analysis. The overall design is experimentally verified by a back-to-back transition which exhibits insertion loss of 4 dB at 300 GHz and 36-GHz bandwidth with better than 10-dB return loss. To evaluate the loss of a single transition, we carried out a loss component analysis by evaluating different lengths of microstrip line and hollow waveguide. The estimated loss for a single transition is 1 dB at 300 GHz. The planar transition without a metal back-short significantly reduces the size of terahertz packages and eliminates the need for additional components for hermetic sealing. The compact transition is easy to integrate in a low-cost LTCC package with an MMIC chip.1167Nsciescopu

300-GHz Corrugated Horn Antennas on LTCC Multi-layered Substrates

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Wideband probe-type microstrip-to-waveguide transition integrated in LTCC

A wideband probe-type microstrip-to-waveguide transition integrated in a low-temperature co-fired ceramic (LTCC) is presented and experimentally verified. To enhance the bandwidth, an air-hole matching structure besides the probe is buried in an LTCC substrate, which is implemented by drilling square holes on different substrate layers. The microstrip-to-waveguide transition is fabricated to verify a design with compact size. The measured results show a good agreement with simulated results.1167sciescopu

300-GHz Microstrip-to-waveguide Transition on a Polyimide substrate Integrated with an LTCC Substrate Integrated Waveguide

A 300-GHz hetero-generous package solution with a combination of a polyimide microstrip-to-waveguide transition on low-temperature co-fired ceramic (LTCC) is presented. To assemble three parts-a metal back-short, polyimide transition, and LTCC substrate integrated waveguide (SIW)-a ridged microstructure beside the microstrip probe was implemented to reduce the air gap on the broadwall of a back-short. A back-to-back transition exhibited an insertion loss of 4.4 dB at 300 GHz and 49-GHz bandwidth with less than a 10-dB return loss. By evaluating loss of the microstrip line and SIW, we estimated the loss for a single transition, which was 0.9 dB at 300 GHz. The probe transition with ridged metal successfully suppressed the unwanted dip in transmission characteristics and eased the difficulty in assembly. The compact transition is easy to integrate in an antenna-in-package with an MMIC chip by combining suitable substrate materials for the transition and package.1132sciescopu

Terahertz device technologies for ultrafast data downburst applications

11Nscopu

Compact THz LTCC Receiver Module for 300-GHz Wireless Communications

A compact, low-cost, fully-integrated package solution has been developed for 300 GHz short-range communication systems. Using low-temperature co-fired ceramic (LTCC) technology, an integrated reflector for the on-chip antenna and high-data-rate signal interconnections including a flip-chip and via transition are embedded in a package. A reduced-size silicon lens antenna is placed in a package cavity together with a flip-chip bonded receiver IC with an on-chip antenna. The overall size of the front-end receiver is only 10 x 10 x 4mm(3), including the 6 mm diameter silicon lens. This compact terahertz receiver, mounted on an evaluation board, demonstrated wireless links with data rates up to 27Gb/s.1198sciescopu

Hydrolysis of tetravalent cerium for a simple route to nanocrystalline cerium dioxide: an in situ spectroscopic study of nanocrystal evolution

Despite the rapid developments in recent nanocrystal research and their expanding applications, the evolution mechanism of nanocrystals remains veiled for the most part due to the lack of appropriate analytical techniques. Here we demonstrate one promising multi-spectroscopic approach for the in situ investigation of nanocrystal evolution. That is, the formation of nanocrystalline cerium dioxide (NC-CeO2) has been probed by dynamic light scattering (DLS), X-ray absorption spectroscopy (XAS) and high-energy X-ray scattering (HEXS). The obtained results indicate that the fine colloidal particles of NC-CeO2 are formed in an acidic aqueous solution simply through the hydrolysis of the initial precursor of small oligomer CeIV species. This information on how NC-CeO2 evolves is fundamental to simplifying and alleviating the synthetic strategy for NC-CeO2 production. © 2013, Wiley‐Vch Verlag