Futoshi Kuroki

Wall-Hanging Type of Self-Complementary Spiral Patch Antenna for Indoor Reception of Digital Terrestrial Broadcasting

A printed spiral antenna with a self-complimentary configuration was developed. This antenna consists of spiral shaped metal strips and slots provided on ground planes as their counterparts. For balanced and unbalanced feeds, two types of antenna configurations such as single and twin spirals were fabricated and their antenna performances were investigated. From evaluation of carrier noise ratio of digital terrestrial broadcasting channels at UHF band, it was confirmed that the presented self-complimentary spiral antenna has capability to apply into an indoor terrestrial broadcasting TV antenna

J-shaped monopole antenna array as an antenna for terrestrial digital broadcasting at UHF band

To develop compact and thin antennas at UHF-band, a printed J-shaped monopole array antenna was discussed for reception of terrestrial broadcasting TV signals. This antenna consists of a folded J-shaped λ/4 monopole antenna array fed by a coplanar waveguide. A simple matching circuit consisting of an open-ended slotted line and high impedance step section were installed between the antenna and the ground plane of the coplanar waveguide to reduce reflection from the antenna. From the analyzed and measured results, it was confirmed that the return loss performance guaranteed the specification of the digital terrestrial broadcasting in the frequency ranges from 440 MHz to 770 MHz. The radiation pattern of this antenna array was similar to that of the monopole antenna and the antenna gain was more than −10dBi. The proposed J-shaped monopole array antenna with the simple matching technique has capability to apply into mobile and indoor terrestrial broadcasting TVs because the antenna size is reasonably small to be constructed in the 1.6mm-thickness paper phenol substrate with an area of 80 mm × 100 mm.

L-Shaped Monopole Array for Terrestrial Broadcasting Reception in the UHF Band

For the purpose of size-reduction, a printed L-shaped monopole array was developed for terrestrial broadcasting reception at UHF-band. This antenna consists of monopole array having L-shaped structure for downsizing, the length of each radiating element being set to be quarter a free-space wavelength in each UHF TV channel. The characteristics were analyzed and measured. According to the analytical results, the antenna gain was 0 dBi on average from 400 MHz to 700 MHz. The antenna was loaded in a handy-type mobile TV and the carrier noise ratios of analog terrestrial broadcasting channels were evaluated. It was confirmed that the proposed L-shaped monopole array is applicable to mobile and indoor terrestrial broadcasting TV antennas. The dimensions of this antenna are 80 mm in width, 50 mm in height, and 1.6 mm in thickness, sufficiently small to be used for such applications.

Giga-bit class ultra high speed signal wireless distribution by using NRD guide technology at 60GHz

A giga-bit class ultra high speed data distribution has been successfully demonstrated at 60GHz by using the nonradiative dielectric waveguide (NRD guide) technologies. An emphasis is placed on a high speed performance of an ASK modulator and a stability of a Gunn oscillator. By assembling these circuit components, ultra high speed NRD guide transmitter and receiver have been fabricated, and it was confirmed that these NRD guide front ends have great advantage of high speed operation capacity beyond 1Gb/s. Moreover, an SDI (Serial/Digital Interface) signal with a bit rate of 1.48 Gb/s was distributed successfully to drive a high resolution HDTV display at 60GHz.

Loss Reduction Technique of Printed Transmission Line at Millimeter-Wave Frequency

Since surfaces of dielectric substrates for printed boards are usually roughened to make tight copper-coating, it was found out that an effective conductivity of a surface of the copper foil, attaching on the dielectric substrate, more degraded than that of an opposite surface of the copper foil, facing an air region, at frequency range beyond centimeter waves. To overcome such difficulty, a technique to reduce transmission losses was devised for printed transmission lines at millimeter-wave frequencies. By symmetrically-loading metal patterns on both sides of the dielectric substrate and by biasing equi-voltage to both metal patterns, the current density on the under surface of the metal pattern decreases, and thus the transmission loss is relatively unaffected by the roughness of the dielectric surfaces. Based on this consideration, a bilaterally metal-loaded tri-plate strip transmission line was fabricated and its unloaded Q factor was measured at 60 GHz, compared with that of a unilaterally metal-loaded tri-plate transmission line. The Q factor of the bilaterally metal-loaded tri-plate transmission line was measured to be 700, while that of the unilaterally metal loaded tri-plate strip transmission line was 200. From the theoretical and experimental investigation, effectiveness of the proposed technique was confirmed.

Range Finding by Using NRD Guide Pulse Radar Front-End at 60 GHz

An NRD guide pulse radar front-end was fabricated for level sensor applications at 60 GHz. Main emphases were placed on circuit configuration and digital signal processing of multi-reflection for short range detection. Typically, an oscillation power is divided by a junction circuit and is introduced into two parts. One is for transmitter, and the other is for LO wave to construct hetero-dyne detection in receiver and the frequency of the former is up-converted so as to be different from the frequency of the LO wave, and thus, an amplifier is installed in the transmitting side due to low power of the up-converted millimeter-wave. In this paper, we proposed a new circuit configuration, which consists of a Gunn oscillator with two output ports to eliminate a junction circuit, a direct pulse-modulator to obtain a high level transmitting power without an expensive millimeter-wave amplifier, and a filter-based down-converter with an up-converter as a local oscillator. Multi-reflection between the radar front-end and target was removed by introducing an FPGA-based digital signal processing including high-speed counting, memorizing, and averaging. Good range finding was performed because the error was less than 1 % for the distance from 2 m to 40 m

High Permittivity Tape Transmission Line for Mass-Productive Dielectric Waveguide at Millimeter-Wave Frequencies

A new transmission media using high permittivity dielectric materials was proposed for mass productivity of dielectric waveguides. This guide consists of a tape-shaped high permittivity dielectric material inserted in the horizontal mid-plane of a below cutoff parallel metal waveguide. It was obvious that this guide exhibited flat dispersion characteristics in a limited bandwidth. The transmission loss was hard to be affected by a loss tangent of the high permittivity material, and thus the low loss performance was exhibited. Assuming the relative dielectric constant of the high permittivity dielectric material to be 200, the single mode bandwidth was calculated to be 40 GHz at a center frequency of 40 GHz, and the transmission loss was estimated to be less than 13 dB/m

NRD guide pulse radar front-end for level sensor applications at 60 GHz

An NRD guide pulse radar front-end was fabricated for level sensor applications at 60GHz. Main emphasis was placed on circuit configuration. Typically, an oscillation power is divided by a junction circuit and is introduced into two parts. One is for transmitter, and the other is for LO wave to construct hetero-dyne detection in receiver. And the frequency of the former is up-converted so as to be different from the frequency of the LO wave, and thus, an amplifier is installed in the transmitting side due to low power of the up-converted millimeter-wave. In this paper, we proposed a new circuit configuration, which consists of a Gunn oscillator with two output ports to eliminate a junction circuit, a direct pulse-modulator to obtain a high level transmitting power without an expensive millimeter-wave amplifier, and a filter-based down-converter with an up-converter as a local oscillator. A maximum sensing distance was found to be 120 m, while that was estimated to be 42 m in the typical pulse radar without an amplifier, and thus the high performance of the proposed radar was confirmed.

NRD guide Gunn oscillator with medium power and low phase noise at 60 GHz

Small sized and high performance millimetre wave source, which consists of Gunn diode mount, circulator and matched load, was developed based on the NRD guide technology at 60 GHz. Main emphasis was placed on compatibility with rectangular waveguide systems. A transition between an NRD guide and a rectangular waveguide was devised and fully optimized by using electromagnetic simulator (HFSS). Good advantages such as a medium level output power of 13 dBm, a small phase noise less than -113 dBc/Hz for 300 kHz offset, and a small frequency stability less than -1.3 ppm//spl deg/C were obtained. The size is smaller than that of a name card. It is confirmed that the performance of the developed Gunn oscillator is higher than that of a commercially available rectangular waveguide type Gunn oscillator from the viewpoint of the output power, phase noise, and frequency stability.

High Permittivity Tape Transmission Line Embedded in Low Dielectric Support at Millimeter-Wave Frequencies

A new guiding structure which consists of a high permittivity tape inserted in a below cutoff parallel metal plate waveguide was proposed for mass productive and low loss dielectric circuits. In this paper, a supporting technique of the high permittivity tape was considered. First, a relative bandwidth versus an aspect ratio of the high permittivity tape was calculated. According to these results, it was obvious that the relative bandwidth was width than that of conventional rectangular metal waveguides when the high permittivity tape was inserted in the vertical mid-plane of the parallel metal plate waveguide. Next, a transmission line which consists of the high permittivity tapes embedded in a low dielectric support was proposed and the transmission characteristics were analyzed. As the result, a wide-band characteristic was obtained because a single mode transmission bandwidth of the lowest order mode was 45 GHz at a center frequency of 50 GHz. In addition, this guide exhibited a flat-dispersion curve in a bandwidth from 40 GHz to 75 GHz and the transmission loss was 15 dB/m in this frequency range.