Japan Radio Wave Industry Develops 20mW GaN Diode

Based on the newly developed GaN diode VCO (lower left) and the transceiver module that uses the VCO (top left). On the right is the transmission system using this transceiver module.

Nippon Denka Co., Ltd. (NDK) has developed a GaN diode with a size of only 13mm × 14mm × 3mm and an output power of 20mW, and has conducted a reference display at the "Japan Microwave Expo". Using this diode in combination with a varactor diode, the 77 GHz band VCO with output power above 10 dBm and phase noise below -100 dBm (at 1 MHz) can be constructed.

According to the narrator, the existing GaN diodes basically use a vertical structure, the package size is larger, generally 3cm × 3cm × 3cm ~ 4cm × 4cm × 4cm, mass production is low. The GaN diodes developed by NDK are flat and have high mass production. Moreover, the package size is significantly reduced to only 13mm x 14mm x 3mm.

According to reports, there are a number of technologies that contribute to the reduction in package size. For example, the use of AlN substrates to improve heat dissipation is effective. According to the narrator, “Al2O3 substrates are generally used. The thermal conductivity of Al2O3 substrates is around 25W/(m·K), while the thermal conductivity of AlN substrates is as high as 230W/(m·K)”.

This GaN diode is now sampling. In addition to the separate supply of diodes, NDK is also able to add additional accessories for processing such as VCOs, detectors and sensors. The narrator said, "We will provide products with excellent usability according to the requirements of our customers." This shows the application of processing GaN diodes into moisture sensors.

This moisture sensor has been applied to the "Millimeter Wave Moisture Measurement System" produced by Nakamura Scientific Industrial Co., Ltd. to measure moisture in plastic pellets. The principle of detection is as follows: Between the millimeter-wave oscillator and the detector, plastic particles are placed as detection objects. Since the millimeter wave can penetrate the plastic, if there is no residual moisture in the plastic particles, the oscillating millimeter wave will all reach the detector; if there is residual moisture, the millimeter wave will be absorbed by the moisture and will not all reach the detector. . According to reports, millimeter-wave moisture measurement system can detect 100ppm level of residual moisture. (Reporter: Yutaro Kojima, Nikkei Electronics)