Woo-Jin Byun

Design of vertical transition for 40GHz transceiver module using LTCC technology

In this paper, we present design, implementation and measurement of 3D mm-wave LTCC (low temperature co-fired ceramic) module with vertical transition through FR-4 PCB substrate. A new structure in order to transfer mm-wave signal from transceiver module through an opening in FR-4 PCB substrate to antenna with standard WR-22 waveguide port is proposed. The module features front-end, receiver and transmitter. The opening in FR-4 PCB substrate is of rectangular type, which has the same dimensions as a WR-22 waveguide. The edge of the opening is conductively plated with copper from top side to the bottom to reduce transmission losses. The implemented module is compact in size (32 x 28 x 3.3 mm ). Experimental results show a 1dB compression output power of 15 dBm and noise figure of 9.72 dB at 40.5~41.5 GHz.

Advanced Power Control Scheme in Wireless Power Transmission for Human Protection From EM Field

The wireless power transmission (WPT) system must guarantee human protection from the electromagnetic (EM) field around the system in proportion to the increase of the transmit power. This paper presents an advanced power control scheme to reduce the EM field. The basic operation of the proposed scheme is the automatic control of the transmit power according to the proximity of the human body within a certain distance from the WPT system. For the initial design, the EM field simulation is carried out using the HFSS 3-D EM simulator. The initial regions around the system are set up according to the EM field simulation results and the human exposure guideline of the 1998 International Commission on Non-Ionizing Radiation Protection (ICNIRP). A WPT system is designed and implemented using the magnetic resonance in order to measure the EM field and confirm the final scheme. The system is operated at 1.8-MHz band to charge a 24-V 40-Ah lead-acid battery embedded in a docent robot. A laser sensor is also used to detect the proximity of the human body. Two communication schemes are used for automatic wireless charging and power control scheme. By the EM field measurement results of the WPT system, the power control scheme is finally confirmed. The performance measurement with a final scheme shows that the EM field is adaptively reduced to less than the guideline value depending on the proximity of the human body.

1.9MHz wireless power transmission system using coupled magnetic resonance

In this paper, a 1.9MHz and 60W wireless power transmission system for a fishing port using coupled magnetic resonances is presented. The proposed wireless power transmission system consists of the 130W class-F power transmitter, two magnetic resonance couplers and 30W full bridge diode rectifier receiver. The transmitter is composed of DDS(Direct Digital Synthesizer) block, class-F power amplifier and communication block to implement the frequency searching and power control function. Two magnetic resonance couplers are designed with a small spiral resonator. The diameter size of the spiral coil is 30cm(1.8 λ /1000). The receiver is composed of full bridge diode rectifier, overvoltage protection (OVP) with active dummy load, DC to DC converter and communication block. For the power control scheme, a communication block is embedded in the transmitter and the receiver. Using the communication block, the message about the error value of the received power is sent by the receiver to transmitter and the transmit power is controlled by transmitter using the received message. The power consumption of the fishing port is about 30W and the total power efficiency of this system is about 40%.

60GHz 2×4 low temperature co-fired ceramic cavity backed array Antenna

Recently, low temperature co-fired ceramic (LTCC) technologies for low cost and small size packaging have been developed in the millimeter wave band. However, in case of designing the antenna of using LTCC substrate, its difficult to meet the bandwidth specification for broadband wireless communication such as IEEE 802.15.3c 60GHz WPAN (Wireless Personal Area Network), which needs 7GHz bandwidth (57∼64GHz), due to the high dielectric constant of LTCC substrate [1]–[2]. Furthermore the radiation efficiency of the antenna becomes reduced due to the surface wave as the height of LTCC substrate becomes increased. Previously a perfect metal cavity backed antenna fed by a coaxial cable [3], antennas using photonic bandgap substrate [4] were proposed to improve the radiation efficiency. Recently, aperture coupling antenna using soft surfaces on LTCC substrate was proposed [5], but bandwidth of the antenna was narrow.

130W power transmitter for wireless power charging using magnetic resonance

In this paper, 130W power transmitter for wireless power charging using the magnetic resonance method is presented. The presented power transmitter is composed of a DDS(Direct Digital Synthesizer) for RF signal generation, a Class-F switching power amplifier for amplifying the RF signal up to 130W output power, a FSK module for communication to the receiver, AC to DC converter for supplying the DC power to components in the power transmitter and a MCU for controlling the output frequency and the output power level. The operating frequency range of the power transmitter is from 1.6MHz to 2.0MHz and the output power control range is from 1W to 130W with 2W step for adopting it to the 1.7MHz band wireless power charging system. To control the output power, the bias voltage of the power amplifier is controlled in the 30V~105V range. The optimal power transmission frequency searching and protection function is applied in the power transmitter using return loss measurement results. For implementing the return loss measurement, a bi-directional coupler and two power detection circuits are used. From the measurement results of the power transmitter the DC to RF power conversion efficiency is over 80% in the 50W~130W output power range. The wireless power charging system is implemented to apply the presented power transmitter. The system is designed to charge a 12V@20Ah LiFePO4 battery which is used for a walking-assistance vehicle. The output power control function is implemented by using the 424MHz FSK communications between the power transmitter and the receiver in order to maintain the power transmission efficiency. The average system DC to DC efficiency is about 50% during the wireless charging.

System level power control algorithm in wireless power transmission for reducing EMF

In this paper, the system level power control algorithm in wireless power transmission for reducing EMF is presented. To design the power control algorithm, EM simulation is carried out using HFSS EM simulator. Depending on the simulation results, the power control zone is set. For the system level power control, the communication between the transmitter and the receiver is adopted by FSK at 433MHz. The magnetic resonance method is used for wireless power transmission system to implement the power control algorithm. The system can transmit up to 100W is designed and implemented for a docent robot that consumes 60W in order to verify the effectiveness of the power control algorithm.

A feasibility study of antenna in a package technology for 40GHz front-end module

In this paper, a front-end module integrated with a planar dipole antenna based on LTCC technology is proposed and its feasibility is studied at 40 GHz band. Front-end module is a part of 40 GHz transceiver and consists of a single pole double throw (SPDT) switch, a laminated waveguide filter and a planar dipole antenna. The proposed structure shows good agreements between measured and simulated results. Size of the proposed structure is 27.5 × 5.85 mm2.

Effect of Eccentricity on the Charge Distribution by a Cylinder-Penetrated Circular Aperture

This letter considers the effect of the eccentricity on the static field and charge distribution for a circular aperture pierced by a long cylinder. The conformal mapping method is used to convert the problem of an eccentric aperture into that of a concentric aperture. The Weber transform, superposition principle, and mode matching are employed to calculate the static potential for this concentric problem. Numerical computations illustrate the behavior of potential distribution, surface charge density, and partial charges on the plane for various aperture eccentricities.

60GHz metallic-rectangular-grooves based reflectarray antenna illuminated by an E-plane sectoral horn feeder

There have been developed a lot of applications such as broadband radio links for cellular base station backhaul networking, imaging to display weapons and non-metal objects, and 60 GHz Wireless Personal Area Network (WPAN) in the millimeter (mm) wave band [1]-[2]. Especially 70- and 80-GHz communication systems within 1-mile distance will play an important role in the next-generation wireless network because the cell site connectivity will demand over 1Gbps data rates. In these bands, highly directional and high gain antenna is needed to compensate for the high free space path loss and not to cause interference. Conventional high gain antennas most often used are parabolic reflectors. Although parabolic reflectors are highly efficient antennas, they are generally bulky in size. Nowadays various flat reflectarray antennas have been presented for the profile size reduction as compared to conventional parabola antennas. Modern planar reflectarrays [3]-[4] have been mainly manufactured by small metallic patched on a dielectric substrate. However the main drawbacks in the development of a planar reflectarray are its narrow bandwidth and lower efficiency. Recently we have proposed metallic-grooves based reflectarray antenna [5] in order to improve bandwidth of a reflectarray antenna illuminated by an open-ended parallel plate waveguide feeder using an overlapping T-block method [6]. In this paper, the performances of antenna gain versus the aperture sizes of feeder for the proposed 2-dimensional antenna are simulated and compared.

Uniformly circular-arrayed OAM mode antenna with radial power divider

Using OAM mode in wireless communication could be a powerful approach to enhance spectral efficiencies. An effective method for making OAM mode antenna with planar patch antennas was proposed. To verify this method, OAM mode (l = +1) antenna which has an 8-way radial power divider and uniformly circular-arrayed patch antennas was designed and tested.