Millimeter-wave Components Research Articles

Handling Technology of Mega-Watt Millimeter-Waves For Optimized Heating of Fusion Plasmas

Millimeter-wave components were re-examined for high power (Mega-Watt) and steady-state (greater than one hour) operation. Some millimeter-wave components, including waveguide joints, vacuum pumping sections, power monitors, sliding waveguides, and injection windows, have been improved for high power CW (Continuous Waves) transmission. To improve transmission efficiency, information about the wave phase and mode content of high power millimeter-waves propagating in corrugated waveguides, which are difficult to measure directly, were obtained by a newly developed method based on retrieved phase information. To optimize the plasma heating efficiency, a proof-of-principle study of the injection polarization feedback control was performed in the low power test stand.

A Novel Multilayer Aperture-Coupled Cavity Resonator for Millimeter-Wave CMOS RFICs

A novel millimeter-wave cavity resonator, completely compatible with commercial CMOS fabrication techniques, has been designed and fabricated in a 0.25-mum CMOS process and tested. The resonator employs a capacitively loaded cavity topology effectively implemented using the CMOS multimetal-layer and via-hole structure. The CMOS capacitively loaded cavity resonator, including two coupling apertures and microstrip feed lines, occupies an area of 2 mmtimes1.4 mmtimes6.28 mum, which is much smaller than the cavity resonator designed without a capacitive load at the same resonant frequency. It resonates at 30 GHz with a corresponding insertion loss of 2 dB and unloaded quality factor of 22.2. The resonant-frequency reduction is approximately 50%, as compared to that without the capacitive load. The design and performance of a new CMOS coupling aperture, which is useful as a coupling mechanism and a vertical interconnect for highly dense millimeter-wave CMOS RF integrated circuits (RFICs) are also presented. The developed low-loss and compact CMOS cavity resonator can be used to realize various millimeter-wave on-chip passive components such as wideband bandpass filters and diplexers and is suitable for direct integration with other CMOS circuits on a single chip. It is attractive for CMOS RFIC design at millimeter-wave frequencies

Observation of Effective Permittivity of Water-Dispersible FePt Nanoparticles at Microwave Frequencies

The 2-4 nm FePt nanoparticles were synthesized by chemical reduction and dispersed into the aqueous solution after the surface modification. The dielectric spectra were measured by an open-ended transmission line technique. An open-ended coaxial cable line was designed to transmit the microwave signals into nanoparticle-filled solutions. The reflection signal revealed the dielectric properties of hydrophobic-coated FePt-filled solution was received by the transmission line. The analysis showed that the effective permittivity was around 70 and down to 50 by the external magnetic field. The flexibility of nanoparticles' permittivity revealed in this study implicates their potential applications ranged from in microwave and millimeter-wave components to biomedical drug delivery system and positron emission tomography scan

Advanced Fabrication Method of Planar Components for Plasma Diagnostics

Kyushu Hitachi Maxell, Ltd, Tagawa-gun, Fukuoka 822-1296, Japan(Received 4 December 2006 /Accepted 11 March 2007)As the importance of plasma imaging diagnostics increases, the fabrication of high performance millimeter-wave planar components becomes essential. This paper describes the development of high performancemillimeter-wave planar components such as antennas and filters using a low-loss fluorine substrate. The prob-lems to be solved are the low degree of adhesion between copper foil and the fluorine substrate and the shape ofthe antenna pattern. In order to solvetheproblems, surface treatment of fluorine films and a fabrication methodusing Electro Fine Forming (EF2) are utilized.

Design of low-cost 183 GHz subharmonic mixers for commercial applications

Techniques are presented for designing fixed-tuned millimetre-wave components with the least number of parts to minimise the cost and maximise the potential for volume manufacture. Design techniques for millimeter-wave mixer components targeted at potentially high volume applications, such as medical and security screening and nondestructive testing, require certain compromises in the use of CAD tools. The compromise techniques are demonstrated using commercially available foundry diodes in the design of a 183 GHz subharmonic mixer for earth observation applications. The resulting mixer exhibits 6.85 dB double sideband conversion loss and a mixer temperature of 988 K using 5 mW of local oscillator power at 92 GHz.

Substrate integrated image guide (SIIG)-a planar dielectric waveguide technology for millimeter-wave applications

A synthesized version of the standard dielectric image guide, called the substrate integrated image guide (SIIG), is proposed and presented. It provides numerous advantages related to fabrication precision, design flexibility, and assembly cost, whereas it still retains the low-loss properties of its conventional counterpart in the millimeter-wave range. This is achieved by artificially lowering the effective dielectric permittivity around a guiding channel through cutting a periodic pattern of air holes in a single high-permittivity substrate. In this way, entire circuits including millimeter-wave components can be fabricated and assembled subsequently by a lamination process. Details on the propagation properties of the SIIG and design rules are presented. Two different simulation approaches, which have proven useful for analysis are described, and theoretical results are validated by measurements of fabricated prototypes. It is shown that guide attenuation values as low as 35 dB/m or 0.07 dB//spl lambda//sub g/ at 94 GHz can be obtained in practice with high-resistivity silicon as a substrate material.

Effect of cable length in vector measurements of very long millimeter-wave components

In millimeter-wave applications, it is sometimes required to measure waveguide components that are several hundred wavelengths long. Depending on the vector network analyzer calibration technique used, the distance between the generator and receiver can be much longer than the one used during calibration when the device-under-test is inserted. If the frequency is swept or drifting, a systematic error is known to appear. A simple way of correcting the result combining two measurements was found.

Highly integrated millimeter-wave passive components using 3-D LTCC system-on-package (SOP) technology

In this paper, we demonstrate the development of advanced three-dimensional (3-D) low-temperature co-fired ceramic (LTCC) system-on-package (SOP) passive components for compact low-cost millimeter-wave wireless front-end modules. Numerous miniaturized easy-to-design passive circuits that can be used as critical building blocks for millimeter-wave SOP modules have hereby been realized with high-performance and high-integration potential. One miniaturized slotted-patch resonator has been designed by the optimal use of vertical coupling mechanism and transverse cuts and has been utilized to realize compact duplexers (39.8/59 GHz) and three- and five-pole bandpass filters by the novel 3-D (vertical and parallel) deployment of single-mode patch resonators. Measured results agree very well with the simulated data. One multiplexing filter, called the directional channel-separation filter, that can also be used in mixer applications shows insertion loss of <3 dB over the bandpass frequency band and a rejection /spl sim/25 dB at around 38.5 GHz over the band-rejection section. LTCC fabrication limitations have been overcome by using vertical coupling mechanisms to satisfy millimeter-wave design requirements. Lastly, a double-fed cross-shaped microstrip antenna has been designed for the purpose of doubling the data throughput by means of a dual-polarized wireless channel, covering the band between 59-64 GHz. This antenna can be easily integrated into a wireless millimeter-wave link system.

Effective permittivity of nanocomposite powder compacts

Advances in nanotechnology have led to a variety of new materials with strong potential applications to microwave and millimeter-wave components, e.g. dispersions of nanoscale particles, nanoparticle-filled polymers, self-assembled nanolattices of magnetic particles. More specifically, the properties of nanocomposites can be tailored for operation as insulators, ferro- and ferrimagnetic materials, highly conductive materials as well, for specific applications. In this study, we have investigated the electromagnetic response at microwave frequencies, using frequency domain network analysis, of cold-pressed powder compacts made of Ni, /spl gamma/-Fe/sub 2/O/sub 3/, Co, and ZnO nanosized powders. Effective complex permittivities of composites over the frequency range (100 MHz-10 GHz) as a function of composition were studied. Within the frequency range of measurements the real and imaginary parts of the effective permittivity of nanocomposites exhibit spectra which can be analytically well represented by power laws. The associated power law exponents, which are similar for the real and imaginary parts of the permittivity, are in the range 0.05-0.20 in agreement with data in the published literature. The dependences of the effective permittivity vs. composition are compared to those obtained from the effective medium theory of Bruggeman, which is found not to be adequate for all nanocomposites studied.

Design of an X-mode swept frequency modulation reflectometer for the measurement of KSTAR plasma density profiles (invited)

An X-mode swept frequency modulation (FM) reflectometry system has been designed to measure the electron density profiles of the “initial” KSTAR plasma. Fast swept HTO oscillators are employed to avoid density fluctuation effects, and frequency quadruplers are utilized to expand the HTO frequency range of 8–18 GHz to completely cover the X-mode cutoff frequency range of 33–66 GHz. The system can also be utilized to measure the edge profiles of the “Day One” KSTAR plasma by either switching from X- to O-mode reflectometry or by employing higher frequency millimeter-wave components and retaining the X-mode reflectometry configuration. To facilitate engineering design and optimization, a 3D drawing tool is utilized to effectively deal with any technical problems that may happen under actual KSTAR conditions. Details of the KSTAR FM reflectometry system are described together with important design issues.

Carrier generation and data transmission on millimeter-wave bands using two-mode locked fabry~perot slave lasers

This paper concerns an optical millimeter-wave signal generator for fiber-based millimeter-wave systems. The millimeter-wave signal generator is based on two-mode injection locking of a Fabry-Perot (F-P) laser. The millimeter-wave signal can be induced by self-heterodyne detection of the locked two modes in a high-speed photodetector (PD). The locking characteristics of the F-P slave laser and the tunability for the millimeter-wave carrier frequency are demonstrated. When the F-P laser is directly modulated by data signals, the locked two modes are modulated simultaneously. The data signals can then be up-converted to the millimeter-wave band at the PD output. By this direct modulation method, the effect of fiber chromatic dispersion on the millimeter-wave signal components at the PD output can be moderate according to mixing of amplitude and phase modulation on the locked two modes. In virtue of the wide response of the F-P laser, relatively high-speed data (2.5 Gbit/s nonreturn to zero (NRZ)-ASK or 622 Mbit/s NRZ-BPSK) on the millimeter-wave band (52 or 60 GHz) can be transmitted on a 32-km single-mode fiber without bit error. A wide tunable range (56-63 GHz) for the central frequency of the millimeter-wave signals and a wide optical bandwidth (1530-60 nm) of the F-P slave laser are also confirmed by the bit-error measurements of the transmitted data signals.

Organic micromachining techniques for mass production of millimeter-wave and submillimeter-wave planar circuits

In this paper we present a range of organic micromachining techniques that enable a planar membrane-based printed circuit to be fabricated on a 5 μm thick organic membrane in the absence of any steps involving thermal oxidation and low pressure chemical vapor deposition. The technologies are suitable for mass production of millimeter-wave or submillimeter-wave components. Transmission losses of a membrane-supported E-plane component are typically less than 0.5 dB/cm.

Finite element analysis of the TE modes in truncated-circular waveguide

Truncated-circular waveguide are used in some microwave and millimeter-wave components. The field patterns in truncated-circular waveguide are desired but usually difficult to be computed by conventional methods. In this paper, they are efficiently determined by using finite element method. The electrical field lines of the dominant TE mode and the first sixteen higher-order TE modes are presented. The calculated results in this paper have important values for us to understand the transmission characteristics of truncated-circular waveguide, and will be of practical significance in designing waveguide components in microwave and millimeter wave engineering.

Artificial Neural Network Models for Coplanar Stripline Synthesis

This paper presents an Artificial Neural Network based coplanar stripline (CPS) synthesis models suitable for microwave Computer-aided design (CAD) applications. The synthesis models were developed by training feedforward neural network with the numerical results of quasi-static analysis. The correlation between the results of developed models and the expected results are greater than 0.999920 for all modeled parameters. The proposed approach is capable of providing accurate CAD models for synthesis of microwave and millimeter-wave components for which accurate analysis models are available whereas accurate synthesis models are not available.

3-D integration of RF circuits using Si micromachining

Micromachined silicon integrated circuits have the potential for providing an overarching circuit integration technology that can significantly reduce the size, weight, and cost of microwave and millimeter-wave components. The capability to integrate diverse substrate technologies opens the door for real multifunction chips, combining analog, digital, RF,and optoelectronic functions. This natural approach to three-dimensional (3-D) vertical integration not only can provide higher density circuits, but, by freeing RF circuit design from the tyranny of the two-dimensional (2-D) layout, can reach levels of performance not possible in a planar geometry. This article focuses on the concept of 3-D circuit integration using silicon (Si) bulk micromachining; however, similar techniques can be applied in any other III-V substrate material. Packaging issues prerequisite for the 3-D integration and component development that led to the capabilities for 3-D integration are discussed. The integration techniques are applied to a 3-D integrated W-band power cube, which provides a vehicle for successfully demonstrating the concept and basic techniques for 3-D integration. A concept study is presented of the use of micromachining to integrate Ka-band 2-D and 3-D corporate power combining architectures.

CAD Models for Coplanar Waveguide Synthesis using Artificial Neural Network

This paper presents Artificial neural network based synthesis models for Coplanar waveguide (CPW) suitable for Computer aided-design (CAD) applications. The CPW synthesis models were basically developed by training the neural network with the numerical results of quasi-static analysis. The developed models have been validated and the correlations between the results of developed models and quasi-static analysis results are greater than 0.999938 for each modeled parameters. The results presented indicate that the developed models retain the accuracy of the quasi-static analysis. The proposed approach is capable of providing accurate and efficient CAD models for synthesis of microwave and millimeter-wave components for which accurate analysis results are available whereas synthesis models are not available or are not accurate over the desired range of operation.

A mode-locked microchip laser optical transmitter for fiber radio

This paper is concerned with the optical domain generation of high-quality millimeter-wave signals for fiber-radio and other applications. The mode-locked millimeter-wave optical transmitter described is based on simple electrooptic microchip laser technology. The transmitter can be designed to operate from a few gigahertz to 100 GHz and beyond. The residual phase noise of the laser is below -100 dBc/Hz at 1-kHz offset, which makes it well suited for optically fed millimeter-wave wireless applications. A key feature of the transmitter is its simplicity, the very small number of elements it employs and the high level of integration of the millimeter-wave and photonic components that results in a small, rugged, and reliable package. The paper describes the design, fabrication, and experimental evaluation of the transmitter.

Matched absorbing medium techniques for full-wave tlm simulation of microwave and millimeter-wave components

This paper investigates the absorbing layer techniques for three-dimensional transmission-line matrix (3d-tlm) simulations. Applications are the full-wave analysis of structures such as microwave and millimeter-wave circuits open to free space. Two approaches are presented, namely the matched layer (ml) and the perfectly matched layer (pml) technique which is used for general cases. For the ml technique, which is efficient for matching guides operating in a quasi-TEM condition, a comparison of the different tlm condensed node is carried out. Concerning the more general case of the pml technique, the theoretical development of a new general three-dimensional (3d) tlm condensed cell is presented. Results pertaining to the characterization of planar circuits are compared with other solutions or measurements. It is found that a proposed unified approach, which includes the tlm simulation for matched layer media, yields very good performance in terms of the absorbing boundary condition (abc).

New Measurements and Assignments in the Millimeter-Wave Spectrum of CD3OH

The ground state rotational spectrum of CD3OH has been revisited in the millimeter-wave range. A total of 216 transition frequencies have been measured and assigned in the 117–179 GHz spectral range, including about 40 transitions previously reported. The spectrum was recorded at the Justus–Liebig University in Gießen, Germany using a frequency modulated millimeter-wave spectrometer. The assignments for the CD3OH transitions were predicted based on energy levels calculated using preliminary results of the global fit of microwave, millimeter-wave, and far-infrared data of Walshet al.(Paper FC04 presented at the 52nd International Symposium of Molecular Spectroscopy, Columbus, OH, 1997). The new measurements have substantially enlarged the accurate millimeter-wave component of the data set available for the global fit and have allowed Walshet al.to obtain significant improvement in the CD3OH molecular parameters (J. Mol. Spectrosc.188,85–93, 1998). The low residuals between observed and calculated frequencies highlight the quality of the global fit results.

Millimeter-wave specular and diffuse multipath components of terrain

Multipath interference data were obtained at a frequency of 95 GHz over pathlengths of 100-250 m by measuring height-gain interference patterns over various types of terrain. Data were collected over grass, lake, ice, snow, concrete, asphalt, and gravel surfaces. The transmit antenna was kept fixed, while the receive antenna translated vertically resulting in grazing angles between approximately 0.5-2.0°. Full illumination of the Fresnel zones was accomplished by broad-beamwidth horn antennas at both ends. Measured interference patterns indicate the presence of both specular and diffuse multipath components. A technique was developed to separate these components by filtering in the spatial Fourier-transform domain by appropriate choice of the notch frequency for the specular component and the bandpass-filter bandwidth for the diffuse components. The notch frequency is chosen according to system geometry considerations. Using this unique separation technique, specular and diffuse reflection coefficients were deduced for various terrain types. The separation technique developed in this paper can be readily applied to existing height-gain data if the system geometry is known.