Harunobu Seita

A Ku-band Dual-SPDT RF-MEMS Switch by Double-Side SOI Bulk Micromachining

This paper presents the design, fabrication method, and measurement results of a low-loss ohmic-contact radio-frequency microelectromechanical systems (MEMS) switch. A novel bidirectional electrostatic actuation mechanism has been developed for a dual single-pole double-throw switch that could be used for an X-Ku-band low-temperature cofired ceramic switched-line-type phase shifter. A high-aspect-ratio deep reactive-ion etching process and a thick gold-plating process were used to develop low-insertion-loss air-suspended MEMS waveguides and low resistive ohmic contacts. A typical insertion loss of 0.56 dB, a return loss of 19.4 dB, and an isolation of 51.4 dB were obtained at a Ku-band frequency of 12 GHz.

Compact and High-Power Spatial Power Combiner by Active Integrated Antenna Technique at 5.8 GHz

Compact and planar active integrated antenna arrays with a high power multi-stage amplifier were developed with effective heat sink mechanism. By attaching an aluminum plate to the backside of the creased amplifier circuit board, effective cooling can be achieved. The nonlinear behavior of the amplifier agrees well with the simulation based on the Angelov model. The high power amplifier circuit consisted of the three-stage amplifier and operated with an output power of 4W per each element at 5.8GHz. The 32-element active integrated antenna array stably operated with the output power of 120W under the effective heat sink design. With a weight of 4kg, the weight-to-output power ratio and the volume-to-output power ratio of the antenna array are 33.3g/W and 54.5cm3/W, respectively. Wireless power transmission was also successfully demonstrated.

A 12-GHz DPDT RF-MEMS Switch with Layer-Wise Waveguide/Actuator Design Technique

A novel design of double-pole double-throw (DPDT) RF-MEMS switch for 12-GHz phase shifter has been developed to minimize the electrical crosstalk between the signal waveguide and electrostatic actuator by allocating them in separate layers of an SOI wafer. Compared with the previous other reports, our design can use relatively large area on the chip to accommodate more electrostatic actuator and to have more electrical ground planes. With this newly developed method, silicon RF-MEMS devices will be able to overcome the drawback of solid-state devices in terms of performance, device size, and cost. This paper reports driving voltage of 4V with the switching speed of 12 microseconds, insertion loss of 3 dB, return loss of 12 dB, isolation of 30dB at 12 GHz.

A 5.8GHz-Band Active Integrated Phased Array Antenna with Wireless Communication and Power Transmission Functions for Space and Satellite Use

Development of a prototype of high power active integrated phased array antenna operating at 5.8 GHz was introduced in this paper. In the AIPAA system for telecommunication as well as wireless power transmission, the two-stage amplifier operated with 27 dBm and insertion loss of the LTCC phase shifter was with 2.6 dB/bit. Under the wireless communication and high power transmission, the BER was measured with less than 10-4 in FSK.

32-element high power active integrated phased array antennas operating at 5.8GHz

There are many sophisticated but high-cost radar systems. However, due to recent progress on wireless electronics technologies, some of them can be realized with compactness and low-cost. One example is a high performance active phased array antenna (APAA). The array antenna is strongly expected to realize in a field of mobile communication as well as that of wireless power transmission such as the Space Solar Power System (SSPS). In order to fabricate the high-performance APAA system with low cost and compactness, there are many technical issues developed in terms of antennas as well as microwave circuits such as small size, light weight, low loss, high power and high efficiency.

An SOI bulk-micromachined dual SPDT RF-MEMS switch by layer-wise separation design of waveguide and switching mechanism

A compact monolithic RF-MEMS switch (2mm × 4mm in area) with the dual single-pole-double-throw (SPDT) configuration was developed by using the SOI bulk micromachining technique. The electrostatic comb-drive actuators and the mechanically movable coplanar waveguides were implemented on the low-resistive active SOI layer and the high-resistive handle layer, respectively, to effectively allocate the device footprint. Electrical crosstalk between the waveguide and the electrostatic actuator was suppressed by using the buried silicon dioxide layer. At a driving voltage of 35V, the switch exhibits an insertion loss of 3dB and isolation of 30dB at 12GHz.

Wireless sensor network in reusable vehicle rocket and low-power 20–30 Ghz amplifier MMIC

This paper proposes a wireless sensor network system in a rocket and describes the architecture of sensor tags. The proposed health monitoring system based on the wireless sensor network employs MIMO communication systems, dual-band; 5GHz for downlink and 24GHz for uplink, and dual power sources; vibration and electromagnetic. The paper also demonstrates a GaAs pHEMT 20-30 GHz band low-power consumption amplifier MMIC for the sensor system. At 1V supply voltage, the amplifier achieves a gain of 11.4dB at 24.5GHz. The power consumption and the output 1-dB compression point are 6.16mW and -0.8dBm, respectively. The MMIC achieves the highest performances of reported 24-GHz amplifier ICs.

A dual-SPDT RF-MEMS switch on a small-sized LTCC phase shifter for Ku-band operation

Integration of Low Temperature Co-fired Ceramics (LTCC) technology and RF-MEMS is applicable for the realization of a small and cost-effective phase shifter. In this paper, a line-switched-type phase shifter with 3D waveguide structures and a novel design of RF-MEMS switch was demonstrated. The design method and fabrication process were reported with experimental results. The insertion loss and phase error of the 4-bit digital phase shifter on LTCC substrates with the size of 8mm × 8mm × 0.55mm was measured to be around 0.5dB/bit and less than 5% at 12.5GHz, respectively. The Dual Single-Pole-Double-Throw (D-SPDT) MEMS switch showed driving voltage of 40V, insertion loss of 0.9dB, return loss of 12dB and isolation of −29dB at 12.5GHz.

C-band energy harvester by Si RFICs with GaN diodes for microwave power transfer

A compact C-band energy harvester is designed, test fabricated, and measured. An RF hybrid semiconductor integrated circuit (RF-HySIC) rectifier was fabricated by comprising a Si RFIC matching circuit and a GaN diode. The energy harvester at 5.8-GHz was made in a multi-circuit fashion under a wide input power range and input power control by field-effect transistor switch. The maximum RF-DC conversion efficiencies from a proto type of RF-HySIC rectifier with 50% and 13% were achieved at 5.1 and 5.8 GHz, respectively.

Hybrid semiconductor integrated recitifer for wireless power transmission into spacecraft

This paper reports on a rectifier with 100 mW class dc output at 5.8 GHz using a gallium nitride (GaN) shottly barrier diode and silicon (Si) matching circuit. The originality of the study lies in its adaptation of the hybrid semiconductor integrated circuit (HySIC) technology that utilizes different types of semiconductors. We have completed the basic steps for developing a rectifier based on the HySIC technology. A nonlinear measurement system of GaN diodes with a jig was constructed and an equivalent circuit model of the diode was established. Based on the diode model, a Si matching circuit was designed. The size of the HySIC rectifier was 3.9 mm×9.5 mm. The RF-dc conversion efficiency of the HySIC rectifier was 10.3% at 5.8 GHz.