Research/RF-MEMS Switch for 5.8GHz Phase Shifter

2019-02-18 (月) 00:26:12 (243d)

Comsat Link with APAA (Active Phased Array Antenna)


総務省受託研究*1の一環として、「高マイクロ波帯用アンテナ技術の高度化技術の研究開発 」というプロジェクトに参加しています。このプロジェクトは、JAXA、京都大学、日本無線株式会社との共同研究で、地上移動基地局の衛星通信に使用する位相アレイアンテナを安価に供給するための技術を開発するものです。平成17年4月からの4年間のプロジェクトとして、現在遂行中です。

Our lab is participating an entrusted research from the Japan MIC *2 R&D project on active phased array antenna system in joint names with JAXA *3, Kyoto University and Japan Radio Co. for four years since April 2006.

MIC APAA Project



Each of our research partners brings its expertise to co-develop APAA *4: JAXA (Prof. T. Takano) undertakes the development of patch array antenna with reduced active nodes and its control LSI. Kyoto University (Prof. S. Kawasaki) develops LNA *5 and LTCC phase shifter circuits. Japan Radio Co. (Mr. T. Suda) makes a package of whole antenna system and components assembly. Our lab at IIS (Prof. H. Toshiyoshi) develops RF-MEMS switches to compose a phase shifter.

A 5.8-GHz Microwave Phase Shifter with RF-MEMS Switches



APAA is an ensemble of tiny patch antennae, and signal to each antenna is individually controlled to tune the delay. As a whole, the antenna array can control the direction of radiation. It can also handle the direction of antenna coupling by the same manner. Phase shifter is to control the delay of microwave signals traveling in the waveguide. In our system, we use an LTCC *7 substrate to accommodate microwave delay lines, and RF-MEMS switches on the LTCC choose the path length to control the phase shift in four bit binary between 0 degree to 180 degrees at 5.8 GHz. Conventional phase shifter used FET transistors or PIN diodes. Compared with them, RF-MEMS switches are expected to have lower insertion loss and higher isolation. We develop RF-MEMS switch of metal-to-metal contact.

An SOI Silicon Bulk Micromachined SPDT RF-MEMS Switch



Our approach to develop an SPDT *9 RF-MEMS is to use the DRIE *10 technique on an SOI *11 substrate. Our target is a device footprint of 1.5 mm by 1.5 mm or smaller operated at 40 Vdc or less and at 0.5 dB loss. After a 5.8 GHz switch, we next aim at applications for 12 GHz or higher.



*1 総務省・電波資源拡大のための研究開発
*2 Ministry of Internal Affair and Communication
*3 JAXA = Japan Aerospace Exploration Agency
*4 Active Phased Array Antenna
*5 Low Noise Amplifier
*6 LTCC = Low Temperature Co-fired Ceramic
*7 Low Temperature Co-Fired Ceramic
*8 Single Pole Double Throw = 1入力2出力型
*9 Single Pole Double Throw
*10 Deep Reactive Ion Etching
*11 Silicon on Insulator