Circular groove guide for short millimeter and submillimeter waves

A new type of groove guide, circular groove guide, has been designed for use as a low losses, high power handling, low dispersion and single mode transmission medium in the short millimetric and submillimetric waves ranges. The characteristic equations of TE modes and TM modes have been developed and the propagation characteristics of the fundamental mode have been discussed. Experimental measurements are in good agreement with theoretical results     

Transmission characteristics of several kinds of closed groove waveguides for millimeter waves

An advantage of closed groove guide over open groove guide is attended. In this paper, the several kinds of closed groove guides including the trapezoidal-, elliptic- and parabolic-groove guides as new types of millimeter wave transmission lines are presented. Their dispersion and cut-off characteristics of the dominant mode are analysed and compared with ones of the closed V-and circular- groove guides by using the equivalent network method. The obtained results have important meaning in theoretical studies and actual applications of groove waveguides.     

Dielectric image line groove antennas for millimeter waves, Part II: Experimental verification

In the first part of this paper the theory of radiation from discontinuities in the ground plane of a dielectric image line has been described. In this second part experimental verifications of the radiation theory as well as millimeter-wave antennas realized on the basis of the theory are described. In the antennas slots and holes in the ground plane of the dielectric image line are used as discontinuities. Experimental results for the radiation characteristics are discussed.     

Dielectric image line groove antennas for millimeter waves, Part I: Theoretical background

Dielectric image line groove antennas are very useful for the application in the millimeter-wave region. In this first part of a two-part paper, three different types of groove discontinuities under a dielectric image line for application in millimeterwave antennas are investigated: the equivalent circuits of 1) a slot discontinuity in a metallic ground plane and 2) a slot discontinuity in the metallization of a substrate material under a dielectric image line are derived theoretically using an approximation for the electromagnetic fields of the slots. 3)The equivalent circuit of cylindrical holes in a metallic ground plane under a dielectric image line is derived from measurements. The results are used to synthesize millimeterwave dielectric image line antenna arrays as described in part II of the paper.     

Fence guide for millimeter waves

A new waveguide, called "fence guide," for millimeter-wave circuitry on a dielectric substrate is described. The structure of the guide, the field distribution, and its characteristics are considered.     

Monolithic rat-race mixers for millimeter waves

In this paper, we report on fully monolithic millimeter-wave Schottky-barrier diode (SBD) down-converters with an IF amplifier using heterojunction bipolar transistors (HBT's). A rat-race circuit is used for the mixer, and is analyzed using a harmonic-balance simulator. The measured conversion gain and the isolation are 7.1 and 29 dB in the V-band design, and 8.0 and 25 dB in the W-band design, respectively. The conversion gains are matched well with the circuit simulation     

A flexible waveguide for millimeter waves

A flexible waveguide section, using a strip of Teflon inserted between two waveguide horns, is described. It is both simple and cheap to construct and has very low loss.     

A ladder structure for millimeter waves

A planar structure, closely related to the stub-supported ring and bar structure, is analyzed using Fletcher's method. The computed dispersion characteristics and interaction impedances show that it should prove useful in millimeter generators. Experiments at X band have shown that oscillation bands of over 1.7 : 1 are possible working on a backward mode. Forward-mode operation with higher output powers, but with a more restricted bandwidth can also be realized.     

Untuned resonators for near millimeter waves

A brief account is given of the reasons for revitalizing an old technique for near millimeter wave measurements. The principles of the method are outlined and the scope of its application indicated. The potential importance of the technique for liquid phase and biological material studies is illustrated.     

Dichroic diplexer design for millimeter waves

Metallic plates of finite thickness perforated periodically with circular holes can be used as diplexers, called “dichroic”, as part of quasioptical multiplexers in the millimetric range. The purpose of this work is to investigate their filtering properties, to provide a method to design dichroic filters in an efficient way and to draw conclusions about their field of application. Computed results are compared to measurements and the design of a diplexer for the breadboard of an atmospheric radiometer is presented.     

Masers and millimeter waves

The characteristics of a number of different kinds of masers are reviewed to estimate their usefulness in the region between one and a tenth millimeter. An estimate of the maximum power output for these systems is made and compared with the output to be expected from mixing two optical signals in a nonlinear dielectric and on a photocathode. Additionally, the noise characteristics of maser amplifiers are briefly reviewed for this region of the spectrum.     

Oversized waveguides and resonators for millimeter waves

If real monolithic systems^* turn out to be impractical at millimeter-wave frequencies, oversized waveguides and resonators are useful alternatives in component and system design. Low losses, high Q factors, and inexpensive manufacturing are their advantages. Starting with an explanation of the term “oversized”, the loss reductions, Q factors, inherently oversized guides, such as the H-guide and its modifications, excitation of higher-order modes, laterally oversized H-guides, and the effects of coupling are described. A brief consideration of applications concludes the presentation.     

A dual-polarized slot antenna for millimeter waves

We describe a new dual-polarized slot antenna to be used with quad-optical devices such as superconductor-insulator-superconductor (SIS) mixers at millimeter and submillimeter wavelengths. The radiation and impedance characteristics of the antenna were obtained from a moment-method calculation. The antenna has an excellent radiation pattern, a low impedance, wide bandwidth, and low cross polarization     

A five-channel grating spectrometer for millimeter waves

A five-channel grating spectrometer for use in millimeter wave band (25～100GHz) is described with its design theory of optical path, and measured results of insertion loss and resolving power.     

A new leaky wave antenna for millimeter waves using an asymmetric strip in groove guide, Part I: Theory

Traveling wave antennas for the millimeter wave range face two main problems: higher metal loss at the higher frequencies, and fabrication difficulties due to the smaller wavelengths. These two problems are addressed here by a new type of leaky wave antenna, in which the fabrication problem is minimized by employing a longitudinally continuous aperture, and the higher loss reduced by basing the antenna on a low-loss waveguide, the groove guide. A longitudinally continuous asymmetric metal strip provides the mechanism that transforms the initially bound mode into a leaky mode. An accurate analysis, based on a transverse equivalent network, is presented here for the properties of this leaky structure that takes into account the mode conversion from the bound mode to the leaky mode. All the constituents of this transverse equivalent network are obtained in closed form, thus yielding a dispersion relation in closed form. Part I of these two companion papers describes the new antenna and its principle of operation, and then derives the parameters of the complete transverse equivalent network. Part II is concerned with the properties of the leaky mode and their relations to leaky wave antenna performance; design considerations together with a variety of numerical results are contained in Part II.     

Overwater propagation of millimeter waves

A field test program conducted to determine the short-and long-term fading characteristics and atmospheric absorption effects on an overwater millimeter-wave transmission path is described. A 6.1-nautical-mile overwater link was established using a 53-GHz transmitting frequency. Low grazing angles were used with antenna heights of 15 to 30 feet above sea level. The results of the program indicate 1) that short-term fading is Rayleigh distributed in the severest cases and is caused by surface reflections, and 2) that long-term fading variations occur more frequently and with greater intensity during warm weather periods.     

Effective excitation of quasi-optical resonator in millimeter wave

It is described effective excitation of quasi-optical resonator (Q. O. R) in millimeter wave (M. M. W) in this article in which some useful results are obtained.     

High performance GaAs quasi-planar varactors for millimeter waves

A novel quasi-planar and highly reliable varactor configuration has been developed to batch fabricate fully passivated GaAs Schottky varactors with near ideal characteristics and state of the art performance. Typically, they exhibit at zero bias a junction capacitance of 0.12 pF and a cutoff frequency in excess of 700 GHz when measured at 70 GHz. As frequency doublers (∼ 35 to 70 GHz) and triplers (35 to 105 GHz), efficiencies greater than 40 and 25 percent, respectively, have been achieved. In a parametric amplifier pumped at 105 GHz and operated in the 55- to 65-GHz signal frequency band, a gain of 14 dB, a 1-dB bandwidth of 670 MHz, and a single sideband noise factor of 5.9 dB were achieved.     

Asymmetrical finline for space applications using millimeter waves

A unilateral finline-the asymmetrical structure finline-is discussed. In addition to providing better electromagnetic isolation, this structure solves problems of mechanical and thermal resistance encountered with the traditional line. It provides better electromagnetic performances than the traditional line, while leaving an additional degree of freedom to obtain the characteristic parameters. Calculation software is used to simulate this type of structure, with results close to experimental measurements. The study was completed by producing two circuits: a 20 GHz bandpass filter and a balanced mixer