Features
Material with Low Permittivity and Low Dielectric Loss for High Frequency Applications
Dielectric substate composing of alumina, pores, and resin is fabricated by using alumina and resin ink. Its dielectric constant is adjusted by appropriately combining the ratio of three materials, and good dielectric loss characteristics are realized for application up to the millimeter wave band.
KEY FEATURES
* In above table, alumina volume percentage is fixed at 60 Vol %. The sum of resin and pore volume percentage is a constant 40 Vol %. The loss tangent values are measured at 10 GHz.
Dk and Df values at 10 ~ 100GHz, which are measured by balanced type circular disc resonator (BCDR)
Smooth Surface of Dielectric Substrate and Silver Metal Trace
Dielectric Substrate and Low Surface Roughness Value
Dielectric substate is fabricated by drop-on-demand (DOD) method of inkjet printing. During the fabrication process, we deposit same amount of alumina (resin) ink in the positions, where every neighboring positions have the same distance.
(a) Alumina droplet formation process. Example of DOD method: (b) Printed droplets on a square lattice and (c) lines
The surface roughness of the dielectric substrate is determined only by that of alumina layer because resin ink is absorbed completely inside the alumina layer by capillary action after it is jetted on it. The surface roughness of the alumina layer deposited by the inkjet printing process is determined by the X and Y axis pitch of alumina ink. By properly adjusting pitch values, it is possible to get the dielectric substrate with small surface roughness value usually less than 1μm.
Silver Metal Trace for Signal Line
Silver metal trace for signal line can be fabricated on the dielectric substrate by using silver ink and the DOD method of inkjet printing. Surface roughness of silver metal trace is usually less than 0.4μm.
KEY SRUFACE ROUGHNESS FEATURES
Coplanar Waveguide and Insertion Loss
A coplanar waveguide (CPW) is fabricated by inkjet printing process and insertion loss is measured. Below is 3D view and cross-section of a coplanar waveguide (CPW) transmission line (Left) and fabricated CPW structure (Right). The dielectric, metal (signal line and GND) formed on the upper surface of the substrate, and vias are all fabricated by the inkjet printing process. The total length and width of the fabricated CPW structure are 9.9 mm and 7.45 mm, respectively. The line width is 0.23 mm and the gap between the line and GND is 0.07 mm, which corresponds to 50 ohms of the used dielectric substrate (Dk =4.3, h=0.25 mm). Vias are implemented in 8 rows on the left and right, the diameter of via is 0.1 mm, and the distance between vias is 0.2 mm. Measured insertion loss is 0.2 dB/mm at 40 GHz. Our product and Rogers RO4003C have similar insertion loss values.
Measured insertion loss up to 40 GHz in a CPW structure. S11 and S21 are Insertion loss and return loss, respectively.
Thermal Conductivity
Thermal conductivity values for CRHM dielectrics composing of alumina (60 volume percent) and resin (40 volume percent) are measured by using DynTIM methods.
Heat Spreading Simulation
We performed simulations of heat spreading in the PCB for two different cases, where thermal conductivity have the following values: (a) 0.2 W/mK (FR4 PCB) and (b) 4.01 W/mK (CRHM PCB)
The heat generated from two heat sources, CPU and memories, is dissipated more effectively in the CRHM PCB than FR4 PCB.
Passed Product Qualification Tests
We carried out environmental and mechanical tests for our substrate. Below is a table for passed product qualification tests.
Design Guidelines for RF Engineering
Below are RF design guidelines.
Media Coverage
아시아경제TV, 2024년 4월6일.
List of partners who signed a Mutual NDA
