Inverted Strip Dielectric Waveguide for Millimeter-Wave Integrated Circuits

A new type of dielectric waveguide, which has a number of advantages over other previously available waveguide structures for millimeter-wave integrated circuits, is described. Dispersion characteristics and the field distributions in the waveguide are calculated using the concept of effective dielectric constant. Field distributions have been measured in the 80-GHz range in order to check the accuracy of the analytical results. This measurement has been done using a novel experimental technique, which should also be applicable to many other millimeter-wave waveguides and components.     

Nonradiative Dielectric Waveguide for Millimeter-Wave Integrated Circuits

A nonradiative dielectric waveguide is proposed in which dielectic strips are sandwiched between two parallel metal plates separated by a distance smaller than half a wavelength. Though the structure is substantially the same as that of the H-guide, it is based on a quite different principle of operation. This dielectric guide is particularly applicable in millimeter-wave integrated circuits, since it is not only small in size, but also allows bends and junctions to be incorporated into the circuits with very little radiation and interference. A design diagram is given. Losses and coupling coefficients of the strips are calculated, as well. Some basic circuit components, such as 90° and 180° bends and T-junctions, made of polystyrene strips, are measured to confirm their usefulness in millimeter-wave integrated circuits.     

Insulated Nonradiative Dielectric Waveguide for Millimeter-Wave Integrated Circuits

An improved version of the nonradiative dielectric waveguide (NRD-guide), called an insulated nonradiative dielectric waveguide, is proposed for millimeter-wave integrated circuits. This dielectric waveguide can overcome some difficulties which arise when high dielectric material is used in the NRD-guide. Guide wavelengths and transmission losses were measured at 50 GHz and compared with theory. In addition, some basic circuit components such as bends, ring resonators, chip resonators, and T-junctions were fabricated on the basis of the insulated NRD-guide and tested to confirm their usefullness in millimeter-wave integrated circuits. The fabricated components operated as expected without suffering from any appreciable radiation at curved sections and discontinuities.     

Experimental Study of Dielectric Waveguide Y-Junctions for Millimeter-Wave Integrated Circuits

Symmetric and asymmetic Y-junctions have been fabricated from rectangular dielectric image line, and the transmission and reflection characteristics have been measured in the 20-26-GHz range. The tested symmetric Y-junction operates as a near 3-dB power divider for the junction half-angle below ~20°. The maximum allowable junction angle of the symmetric Y-junction is discussed, which is very important for millimeter-wave integrated-circuit applications. It is shown that the asymmetric Y-junction can be used as a directional coupler because of the controllable splitting ratio and high isolation. The results for the asymmetric Y-junction with a gap are also presented.     

New Waveguide Structures for Millimeter-Wave and Optical Integrated Circuits

Some new dielectric waveguide structures suitable for millimeter-wave and optical integrated circuits are presented. A method of analyzing wave propagation in these guides is developed by assuming simple field distribution and approximating the various regions of the guides in terms of effective dielectric constants. The mathematical formulation utilized results in simple eigenvalue equations from which the dispersion characteristics of the waveguides are readily obtained. Experimental results are described and the agreement between theory and experiment is shown to be quite good.     

Design of Dielectric Ridge Waveguides for Millimeter-Wave Integrated Circuits

All-dielectric ridge waveguides may be useful as elements of millimeter- and submillimeter-wave integrated circuits; A planar metallic V-coupler can be used to couple energy between the guide and small circuit elements such as diodes. Desirable characteristics in such a guide/coupler system are a) quasi-single mode propagation; b) low radiation loss in bendy c) low coupling loss between guide and devices and d) adequate physical strength. In this paper, we discuss the general problem of designing guides and couplers to obtain the desired characteristics. The principal method used is simulation in the range 2-7 GHz. We find that with good compromise designs, typical coupling loss between waveguide and a small device is about 1.4 dB, exclusive of dielectric loss and ohmic loss in the coupler.     

Electronic Phase Shifter for Millimeter-Wave Semiconductor Dielectric Integrated Circuits

A new system is proposed for millimeter-wave integrated circuits. It is suggested that high-resistivity silicon be used as a medium for a dielectric waveguide. With the advent of high-resistivity silicon, propagation can occur with relatively low Ioss. Furthermore, since the medium is a semiconductor compatible with active devices, it is proposed that active devices can be constructed directly in the semiconductor dielectric guide or appendaged directly on the surface. The basic approach is similar to that used in integrated optics, except that the medium for millimeter-wave guidance is a semiconductor and the control devices rely on conductivity modulation rather than on electrooptical effects. Some particular devices suggested are oscillator, mechanical and electronic phase shifters, amplitude modulators (switches), and detectors. The first of such devices investigated has been the electronic phase shtiter. Related theory and experiments are reported here. In addition, preliminary results on oscillators imbedded in a dielectric resonator are presented.     

Low-Loss Rectangular Dielectric Image Line for Millimeter-Wave Integrated Circuits

This paper describes some fundamental properties of a low-Ioss E/sub 11//sup x/ mode rectangular dielectric image line where the electric field is parallel to the metal image plane. This image line is characterized by its low transmission loss, compared with the conventional dominant E/sub 11//sup y/ mode rectangular dielectric image line. The transmission loss of this new image line is nearly less than half that of the E/sub 11//sub y/ mode rectangular dielectric image line. As an application example, a bandpass filter is developed using this E/sub 11//sup x/ mode rectangular dielectric image line and the measurement results of its frequency responses in the 50-GHz range are presented. Although the E/sub 11//sup x/ mode is a higher order mode in the rectangular dielectric image line, reasonable bandpass filter characteristics have been realized.     

Millimeter-Wave Integrated Circuits

Monolithic millimeter-wave integrated circuits have been designed and fabricated on semi-insulating GaAs substrates using microstrip transmission lines. Circuits using hybrid techniques have also been constructed on quartz and ceramics. This paper shows that microstrip-line integrated circuits are feasible at millimeter-wave frequencies. Circuit functions have been constructed and tested in the 25- to 100-GHz range. The loss in microstrip line on semi-insulating GaAs was found to be less than 0.3 dB/ /spl lamda/. Couplers from waveguide to microstrip have been made with transmission losses less than 0.5 dB. Monolithic integrated detectors showed 5-dB better sensitivity than a 1N53 diode in a Philips detector mount. Monolithic diodes delivered 1.5 mW at 28 GHz. The results are encouraging and a fully monolithic integrated receiver is under development.     

Millimeter-Wave Integrated Circuits

Monolithic millimeter-wave integrated circuits have been designed and fabricated on semi-insulating GaAs substrates using microstrip transmission lines. Circuits using hybrid techniques have also been constructed on quartz and ceramics. This paper shows that microstrip-line integrated circuits are feasible at millimeter-wave frequencies. Circuit functions have been constructed and tested in the 25- to 100-GHZ range. The loss in microstrip line on semi-insulating GaAs was found to be less than 0.3 dB//lambda/. Couplers from waveguide to microstrip have been made with transmission losses less than 0.5 dB. Monolithic integrated detectors showed 5-dB better sensitivity than a 1N53 diode in a Philips detector mount. Monolithic diodes delivered 1.5 mW at 28 GHz. The results are encouraging and a fully monolithic integrated receiver is under development.     

Analysis of a Metal-Coated Planar Dielectric Waveguide with Chiral Cladding

The propagation characteristics of a metal-coated planar waveguide with chiral media filled in the cladding are presented. The effects of chirality on cutoff, dispersion characteristics and field distributions of the waveguide are studied. The results show that cladding chirality brings phase chopping to the transverse electric field component of those modes with odd mode numbers.     

Analysis of Planar Dielectric Waveguide with Chiral Cladding

The propagation characteristics of a planar waveguide with chiral media filled in the cladding are presented. The effect of chirality on cutoff, dispersion and field distribution of the waveguide are studied. The results show that the cladding chirality may lead to a single-mode operation in the planar waveguide.     

Channel Dropping Filter for Millimeter-Wave Integrated Circuits

The dielectric waveguide structure finds various applications in integrated circuits for the millimeter-optical-frequency range. Many passive and active devices, using dielectric waveguide, have been developed. From the viewpoint of Iow-loss property, the dielectric rectangular waveguide seems to be more suitable for integrated circuits. This paper describes the design method and experimental results for channel dropping filter using dielectric rectangular waveguide. Some experimental investigations of the dielectric rectangular waveguide properties are also presented. The channel dropping loss of the filter is 1.5 dB at a channel center frequency of 52 GHz with a 180-MHz 3-dB bandwidth. Experimental results agree fairly well with the theoretical calculations.     

A Parallel-Plate Waveguide Approach to Microminiaturized, Planar Transmission Lines for Integrated Circuits

The parallel-plate waveguide with a two-layer loading medium, a conducting semiconductor substrate, and a relatively thin dielectric layer approximates the interconnections in many integrated systems if the fringing fields are ignored. The fundamental mode of this structure is an E mode which is a surface wave. Its propagation behavior is analyzed in this paper and the equations are evaluated by highly accurate numerical methods. The semiconducting substrate is characterized by its dielectric constant and conductivity. A critical conductivity /spl sigma//sub min/ exists and is related to the cross sectional and material parameters. If the substrate conductivity is given by /spl sigma//sub min/ then the attenuation constant of the line is a minimum. The same value of conductivity yields minimum phase distortion at maximum bandwidth. If the conductivity is larger than /spl sigma//sub min/ the substrate acts as a poor conductor with associated skin effect; if it is smaller, lossy dielectric behavior results. Analysis shows that it is appropriate to subdivide the frequency range into three intervals. The lowest-frequency interval is characterized by propagation which resembles diffusion. This is caused by the loss in the dielectric layer. The next frequency range extends to some upper frequency which is determined by substrate conductivity and the cross-sectional dimensions. In this interval, the phase velocity of the fundamental mode is controlled by the ratio of dielectric to semiconductor thickness, which, if typical interconnections are considered, implies a very low velocity. This property indicates that the structure can serve as a delay line. Further increases in frequency result in higher phase velocities. Skin effect and dielectric loss behavior describe the propagation in this third interval.     

Analysis of Slow-Wave Coplanar Waveguide for Monolithic Integrated Circuits

The slow-wave characteristics of an MLS coplanar waveguide are analyzed using two different full-wave methods mode-matching and spectral-domain technique. The theoretical results obtained with them and the experimental values are in good agreement. Several important features of the MIS coplanar waveguide are presented along with some design criteria.     

Rigorous Analysis of the Step Discontinuity in a Planar Dielectric Waveguide

Planar dielectric waveguides play an important role in electrooptics and in the submillimeter regions. In many laser configurations and integrated optical components, grooves are etched in the planar surface or overlays are deposited on it. The step is an idealization of such discontinuity. In this paper, the problem of an arbitrary large step under multimode excitation is solved by means of a rigorous variational approach. A rapidly converging expression for the scattering matrix of the step is derived, which is analogous to the one previously derived for transverse discontinuities in closed waveguides. Two choices as to the basis functions are compared: one is constituted by optimally scaled Laguerre functions and the other by the surface waves of both slabs complemented by Laguerre functions. Both the electric field and the magnetic field formulations of the problem have been investigated for the TE case. Numerical results are presented for the scattering matrix of the step under monomode and multimode excitation as well as for its radiation pattern. The accuracy and limitations of existing small step approximations are discussed. The technique is applicable to other transverse discontinuities in open structures.     

Modified Wilkinson Power Dividers for Millimeter-Wave Integrated Circuits

A modification of the Wilkinson power divider is presented that eases planar implementation while maintaining performance. By adding transmission lines between the resistor and the quarter-wave transformers of the traditional design, a range of valid solutions exists that meet the conditions of being reciprocal, isolated between the output ports, and matched at all ports. The proposed design is particularly useful at millimeter-wave frequencies where reduced physical dimensions make a circuit configuration suitable for low-cost package-level implementation difficult using traditional methods. Two frequency bands are demonstrated. At V-band, the circuit gives 0.3-dB excess insertion loss, 19-dB isolation, and 50% bandwidth. At the W-band, the circuit gives 0.75-dB excess insertion loss, 24-dB isolation, and 39% bandwidth.     

A Periodic Branching Filter for Millimeter-Wave Integrated Circuits

A number of passive and active devices using dielectric waveguides have been developed and find various applications in integrated circuits at the millimeter optical-frequency range. The design, theoretical considerations and experimental findings of a periodic branching filter using rectangular dielectric waveguides are described in this paper. Low insertion loss for the periodic branching filter with 850-MHz 3-dB bandwidth, less than 1.0 dB, is achieved in the frequency range from 77 to 85 GHz. Measured results are in good agreement with theoretical calculations.     

A V-Band Communication Transmitter and Receiver System Using Dielectric Waveguide Integrated Circuits

A V-band communication transmitter and receiver is described. Both units make extensive use of passive microwave components fabricated rising millimeter-wave insular line integrated circuits (MILIC's). These components consist of rectangular dielectric rod antennas, a MILIC ferrite isolator, a bandpass ring filter, a directional coupler, and sections of dielectric insular waveguide. The passive insular waveguide components are integrated together, along with split block metal waveguide mounts for the active devices, in order to form the RF circuitry of the transmitter and receiver.     

Generalized Coupled Dielectric Waveguide and its Variants for Millimeter-Wave Applications

The characteristic equations of hybrid TM and TE modes for a generalized coupled dielectric waveguide are derived using the mode-matching technique. From the characteristic equations of the generalized coupled dieketric waveguide, the phase constant, wave impedance, and field distribution can be evaluated. A variety of single and coupled dielectric waveguides can be obtained by assigning proper parameter values to the generalized coupled dielectric waveguide.