Circulators for microwave and millimeter-wave integrated circuits

The requirements for circulators for use in combination with microwave and millimeter-wave integrated circuits are reviewed, with special emphasis on modules for phased-array antennas. Recent advances in broadbanding and in miniaturization are summarized. Novel types of circulators that are fabricated by attaching a ferrite disc and a suitable coupling structure to the surface of a dielectric of semiconductor substrate (quasimonolithic integration) are described. Methods for achieving complete monolithic integration are also discussed     

Shielded passive devices for silicon-based monolithic microwave and millimeter-wave integrated circuits

This paper introduces floating shields for on-chip transmission lines, inductors, and transformers implemented in production silicon CMOS or BiCMOS technologies. The shield minimizes losses without requiring an explicit on-chip ground connection. Experimental measurements demonstrate Q-factor ranging from 25 to 35 between 15 and 40 GHz for shielded coplanar waveguide fabricated on 10 /spl Omega//spl middot/cm silicon. This is more than a factor of 2 improvement over conventional on-chip transmission lines (e.g., microstrip, CPW). A floating-shielded, differentially driven 7.4-nH inductor demonstrates a peak Q of 32, which is 35% higher than an unshielded example. Similar results are realizable for on-chip transformers. Floating-shielded bond-pads with 15% less parasitic capacitance and over 60% higher shunt equivalent resistance compared to conventional shielded bondpads are also described. Implementation of floating shields is compatible with current and projected design constraints for production deep-submicron silicon technologies without process modifications. Application examples of floating-shielded passives implemented in a 0.18-/spl mu/m SiGe-BiCMOS are presented, including a 21-26-GHz power amplifier with 23-dBm output at 20% PAE (at 22 GHz), and a 17-GHz WLAN image-reject receiver MMIC which dissipates less than 65 mW from a 2-V supply.     

Microwave and millimeter-wave integrated circuits

This historical review is divided into three sections: microwave integrated circuits (MICs), monolithic microwave integrated circuits (MMICs), and MIC and millimeter-wave integrated-circuit applications     

Characterization of buried microstrip lines for constructinghigh-density microwave integrated circuits

This paper describes the characterization of a guided wave structure, buried microstrip line (BMSL), which is considered to be promising for constructing high-density microwave and millimeter-wave integrated circuits because of its high isolation characteristics. The BMSL includes a dielectric medium surrounded by ground conductor walls and a strip conductor on the top of the dielectric. The BMSL structure is characterized by the two methods, the rectangular boundary division (RBD) method and the finite-difference time-domain (FDTD) method. The RBD method is employed to obtain basic parameters of the BMSL such as characteristic impedances and coupling coefficients over a wide range of line sizes taking advantages of its high calculation efficiency. On the other hand, the FDTD method has been used for more detailed characterization such as the frequency performances of stub matching circuits. The FDTD method is also used to confirm the validity of the quasi-TEM wave approximation which the RBD is based on. The analysis results reveal that the BMSL structure possesses much lower coupling coefficients than a conventional microstrip line does, from -15 dB to -100 dB depending on their burial depths     

Synthetic quasi-TEM meandered transmission lines for compacted microwave integrated circuits

This paper presents a two-dimensional transmission line (2-D TL) that supports quasi-TEM propagation mode and reduces problems associated with compacted meandering of microstrip (MS) on propagation constants and the characteristic impedances commonly observed in conventional one-dimensional MSs. The proposed 2-D TL comprises two layers of metallic surfaces on either side of a dielectric substrate. The top metal surface is a meandered connection of a unit cell with a central patch and connecting arms. The bottom surface is a meshed 2-D periodical ground plane, whose etched portion complements the patch portion of the top surface, forming a complementary-conducting-strip (CCS) TL, enabling a combination of an MS and MS with the tuning septa in a unit cell. Both theoretical and experimental investigations of the CCS TL agree well and demonstrate that it is much less susceptible to the effects of meanderings on the propagation constant and characteristic impedance than an MS for the same meandered pattern. Two design examples are presented to demonstrate the potential for a CCS TL for miniaturizing microwave passive circuits with minimal losses. The first example involves a 5.4-GHz CCS four-port rat-race hybrid realized in RO4003 and reduces the area of original MS design by 87%. The second example illustrates the applicability of a CCS TL to a monolithic RF integrated circuit using a first-pass design of a 5.2-GHz CMOS oscillator incorporating a CCS TL as a resonator with an area totaling 500/spl times/600 /spl mu/m/sup 2/ including pads base on Taiwan Semiconductor Manufacturing Company's 0.25-/spl mu/m 1P5M CMOS process techniques.     

New multilayer planar transmission lines for microwave andmillimeter-wave integrated circuits

New types of planar transmission lines employing multilayer structures are proposed for possible applications in microwave and millimeter-wave integrated circuits. Detailed investigations are presented through numerical results calculated using the spectral domain technique. The newly proposed transmission lines have many attractive features such as a large impedance range, flexibility and ability to realize complicated, densely packed integrated circuits, as well as miniaturization through the use of thin dielectric layers. Additionally, they possess all of the inherent advantages of the CPW and microstrip line. Their use in microwave circuits is exemplified through a low-pass filter realized using the new slot-coplanar lines with less than 0.5-dB insertion loss and better than 20-dB return loss. The filter's measured and calculated performances also agree well     

Spectral domain analysis of eigenmodes in a shielded multilayer coplanar waveguide for microwave and millimeter-wave integrated circuits

Coplanar waveguide has found increasing use in microwave and millimeter-wave integrated circuits, and a knowledge of its eigenmodes is very useful for circuit design. In this paper, we determine the dispersion properties of the eigenmodes in a shielded multilayer coplanar waveguide using the spectral domain approach. Numerical results of the propagation constants for different combinations of dielectric materials are presented to illustrate the behaviors of the eigenmodes.     

多层微波集成电路中微带线层间互连仿真

针对多层微波集成电路设计的微带线层间互连问题,介绍了垂直通孔互连、垂直带条互连和层耦合过渡互连三种高性能的互连方法,并且采用三维电磁仿真软件HFSS对这三种互连结构进行了建模和仿真.仿真结果表明,垂直通孔互连和垂直带条互连在0.1~25 GHz的频宽范围内,回波损耗S11<-20 dB,插入损耗S21>-1 dB,互连性能优良,而层耦合过渡互连在20~68 GHz内回波损耗S11<-20 dB,插入损耗S21>-1 dB,具有在毫米波频段实现互连的潜力.     

GaAs HBT's for microwave integrated circuits

The status of the microwave GaAs heterojunction bipolar transistor (HBT) technology is reviewed. Microwave circuits for advanced military and commercial systems continue to increase their dependence on the performance, functionality, and cost of active components fabricated using solid-state technology. The performance advantages provided by GaAs HBT's, for several critical circuit applications, have stimulated a worldwide development activity. Progress in HBT device technology and microwave circuit applications has been extremely rapid because of the broad availability of III-V compound semiconductor epitaxial materials and prior experience with GaAs field-effect transistors (FET's) and monolithic microwave integrated circuits (MMIC's). The great flexibility of HBT's in microwave circuits makes them prime candidates for applications in complex multifunctional microwave/digital IC's in next-generation systems     

Numerical through-resistor (TR) calibration technique for modeling of microwave integrated circuits

A through-resistor (TR) calibration procedure is proposed for parameter extraction and accurate modeling of planar discontinuities and circuits by using a full-wave technique such as method of moments (MoM). This new scheme allows the effective use of a commercial electromagnetic field simulator in removing inherent numerical noises or errors in simulation, and making the parameter extraction for circuit models. A microstrip open-end and a microstrip gap are studied and effectiveness of this new scheme is verified.     

Measurement techniques for monolithic microwave integrated circuits

Introduces the basic technologies that are associated with measurements of monolithic microwave integrated circuits. The use of test fixtures and wafer probe stations at ambient room temperature is reviewed and their role at thermal and cryogenic temperatures is discussed. With the increasing need for performing non-invasive measurements, advances in experimental field probing techniques are explored     

Uniplanar techniques for monolithic microwave integrated circuits

`Uniplanar' techniques have recently been introduced for the design of monolithic microwave integrated circuits (MMICs). The aim of these techniques is to achieve a higher level of integration of circuitry and to overcome the need for through-substrate via holes and the related back-face processing steps. This is achieved by using coplanar waveguide (CPW), slotline, and miniature `thin-film microstrip' transmission-line media as opposed to conventional microstrip. The design and performance of a number of uniplanar MMIC couplers, amplifiers, and other test circuits fabricated using the GEC-Marconi (Caswell) foundry are described     

Thin ferrite devices for microwave integrated circuits

This paper is intended as a review of developments which allow ferrite materials in a planar geometry to be used in the realization of magnetic devices which are compatible in form with other microwave integrated circuits. These devices include phase shifters (reciprocal and nonreciprocal), latching circulators, isolators, and phase and amplitude modulators. The application of some of these devices is demonstrated in the form of electronically steerable array antennas.     

Modified suspended striplines for microwave integrated circuits

Suspended coupled striplines have very different even- and odd-mode phase velocities. A structure modified by the presence of a slot is proposed to obtain equalisation, a condition necessary to build broadband couplers. This modification has the advantage of preserving the suspended configuration.     

Film technology in microwave integrated circuits

A review of the material technology for microwave integrated circuits (MICs) is presented. The types of microwave circuit media that have been used are described and classified as a function of the amount of size reduction or integration which corresponds to the effective dielectric constant of the media. The materials used for substrates, conductors, dielectrics, and resistors are considered in terms of the requirements for microwave circuits. The fabrication of multilayered thin-film circuits and the various thin-film combinations that have been used in MICs are discussed. The various loss contributions for microstrip circuits produced by thin- and thick-film technology and substrate material are compared with each other as a function of frequency. It is concluded that microwave circuits operating at frequencies 2 GHz and above require thin-films on pure smooth substrates.     

Equivalent circuit models in current-mode circuits for time delay calculations

In this paper time delay calculations for current-mode circuits are considered and equivalent circuit models for delay estimation are developed. Three different equivalent circuit structures for the Core Circuit used in the multipurpose IC DU-TCC1209 are examined separately; however the relation obtained for the time delay can be applied to any CMOS current-mode circuit. The proposed calculation methods are verified with SPICE using 0.35 μm TSMC MOSIS technology parameters and with bench-test measurements using DU-TCC1209.     

Layer assignment for printed circuit boards and integrated circuits

The layer assignment problem arises in printed circuit board (PCB) and integrated circuit (IC) design. It involves the assignment of interconnect wiring to various planes of a PCB or to various layers of interconnect wires in an IC. This paper reviews basic techniques for layer assignment in both PCBs and ICs. Two types of layer assignment are considered: (1) constrained layer assignment in which routing of interconnections is given and the objective is to assign wires to specific layers, and (2) unconstrained, or topological, layer assignment, in which both the physical routing of interconnections and assignment of the wires to layers is sought. Various objective functions, such as via minimization and minimization of signal delays through interconnect lines are discussed     

Multisectional modeling of high-speed electrooptic modulators integrated in a microwave circuit CAD environment

We present a new multisectional model for high-speed electrooptic modulators, fully integrated within the framework of a microwave circuit computer-aided design (CAD) suite (MWOFFICE). Starting from geometrical and layout parameters, the model allows both simple (traveling-wave) and complex (phase reversal, periodically loaded) structures to be assembled, analyzed, and optimized from the standpoint of the electrical and electrooptic response (including chirp effects) both in small-signal (analog) and in large-signal (digital) operation, exploiting standard simulator tools. At no additional effort, parasitic and passive elements (such as optical or electrical delay paths) can be directly included in the modulator schematic, and the effect of transitions and package parasitics can be readily accounted for at a circuit level. Moreover, model integration within a circuit CAD suite enables one to seamlessly perform driver and modulator design and optimization within the same monolithic or hybrid circuit environment. Comparisons with experimental and literature data and design examples are presented to validate the approach and stress its potential in the design of high-speed electrooptic modulators.     

Approach for heat sinks in monolithic microwave integrated circuits

A planar electrode, placed at the symmetry plane of the odd mode of coupled microstrip, is proposed as a means for heat-sinking active devices in monolithic microwave integrated circuits.     

Modelling of coupled interconnect lines for integrated circuits

A coupled interconnect model is developed using even mode and odd mode capacitance analysis. Signal coupling is presented in terms of interconnect width, substrate thickness, interconnect line spacing, and frequency. Picosecond photoconductor based measurements of coupled transmission lines on the integrated circuit support the even and odd mode signal transmission simulation results. SPICE circuit simulation is used to demonstrate the model utility and explore the sensitivity of the self- and mutual capacitances and inductances in signal crosstalk.