Mutual coupling between slots printed at the back of ellipticaldielectric lenses

This paper presents calculations of the mutual admittance between two slots on a ground plane that are the primary feed of an elliptical dielectric lens antenna. This admittance may also be regarded as the basic constituent of a Galerkin method of moments formulation for the analysis of more complex feeding arrangements of slot antennas and coplanar waveguide circuits, it is found that the contribution of the reflection mechanisms inside the lens significantly affects the mutual admittance especially for H-plane coupling     

Crosstalk reduction in mixed-signal 3-D integrated circuits with interdevice layer ground planes

We show nearly 8 dB of crosstalk reduction using ground planes between active device layers in three-dimensional (3-D) integrated circuits. Our experimental work utilizes two planes of MOS transistors with tungsten or polysilicon ground planes designed to attenuate crosstalk. Theoretical simulations, using an electromagnetic solver, and the experimental results are consistent with analytical results. The key result verified is that a ground plane, whose footprint shadows the device area, is sufficiently large for effective attenuation. The interdevice layer ground plane provides an effective means to achieve crosstalk reduction in 3-D mixed-signal/RF integration because of simple fabrication and high coupling isolation.     

Composite effects of reflections and ground bounce for signal line through a split power plane

The signal propagating along a microstrip line over a slot on the power plane will suffer from composite effects of reflected noise by a discontinuity in signal return path and ground bounce between power and ground planes. A new equivalent circuit model is proposed and simulations are performed for multilayer structures to characterize these composite effects. An experimental setup is devised to demonstrate significant coupling between signal lines due to the slot-induced ground bounce. Favorable comparison between the simulation and measured results validates the proposed equivalent circuit model and analysis approach.     

Broad-band thin-film signal sampler

Previous developments in high frequency signal sampling have been extended by applying thin-film and solid state techniques to the sampler design. The basic elements of a sampler are a signal-carrying transmission line, a sampling gate, a drive line for the gate pulse, and a video output. In the design reported here, a thin quartz substrate supports the circuits. To reduce signal-line reflections the gate is made the center element of a low-pass signal-line filter. The gate pulse is developed across a length of slot transmission line in the signal ground plane parallel to and beneath the signal transmission line. A beam-lead Schottky diode pair is mounted across the slot with its center node connected to the signal transmission line through the substrate.     

Reduction in Reflections and Ground Bounce for Signal Line Over Slotted Power Plane Using Differential Coupled Microstrip Lines

This paper investigates the noise reduction in the slot-induced ground bounce noise by using differential signaling. An efficient 2-D finite-difference time-domain method together with equivalent circuits for both the differential line and the slot is established and simulations are performed for a three-layer structure to characterize the ground bounce coupling. A simple model is then proposed to understand how the differential coupled microstrip lines can help reduce ground bounce. Different factors which affect noise reduction are investigated, such as the coupling coefficient, rising time, skew of differential signaling, and structure asymmetry in slotline. An experimental setup is devised to demonstrate the noise coupling between signal lines due to the slot-induced ground bounce and significant noise reduction by employing differential signaling. A favorable comparison between the simulation and measured results validates the proposed equivalent circuit model and analysis approach.      

CPW馈电缝隙耦合蝶形毫米波贴片天线

该文研究了一种工作在Ka波段共面波导(CPW)馈电缝隙耦合的蝶形贴片天线。耦合缝隙位于接地板上,而不需要额外的缝隙耦合层,使天线更易与电路相集成。耦合缝隙的存在改变了接地板上原有表面电流的分布,使电流沿着缝隙边缘流动,因此馈线与辐射源的电磁耦合效率得到提高。用有限元分析软件(Ansoft HFSS)对衬底厚度、贴片角度、耦合缝隙大小等参数变化时的天线性能进行了仿真。比较并分析了S11,增益等天线性能参数的变化规律,并在带宽最优的条件下给出了一组参数值,此时天线的工作频率为35.5GHz,带宽为1.22GHz,增益为6.38dB。     

Differential Dual‐Frequency Antenna for Wireless Communication

A novel differential dual‐frequency antenna using proximity coupling is proposed. Dual bands are realized by a slot in the ground plane. The lower resonant frequency is controlled by the slot in the ground plane, and the upper resonant frequency is mainly determined by the dimensions of the radiating patch. Measured results show that the proposed antenna can operate at 2.51 GHz and 5.38 GHz.     

Design of microwave amplifier using nonresonant slot matching

A study into the application of nonresonant slots for impedance matching in microwave circuits is presented based on an evaluation of the performance of a low noise microwave transistor amplifier. Results show improved gain and noise figure characteristics for a slot matched amplifier compared to a microwave amplifier designed using transmission line stubs. Since the slots that are proposed appear in the ground plane of the active circuits, the size of the overall circuit is lower compared to that of an amplifier designed using transmission line stubs     

Miniature Strip-Line to Waveguide Slot Adapter--Co-Linear (Correspondence)

An inline adapter from miniature air dielectric strip transmission line with a ground plane spacing of 0.130 in to half height X-band waveguide has been developed by the Microwave Design Group at Hycon Manufacturing Company, Monrovia, Calif. The upper wall of the waveguide was used as the lower ground plane for the strip-line. Unity coupling was accomplished through a transverse slot in the common wall. The slot was 0.066-in wide by 0.750-in long surrounded by a metal cavity 0.250 in by 1.000 in built into the ground planes. (See Fig. 1.) The slot junction was matched by use of tunable shorts both in the strip-line and the waveguide. The output of the 50-ohm stripline was terminated by a built-in strip-line load whose VSWR was 1.04.     

A Generalized 2-D Multiport Model for Planar Circuits With Slots in Ground Plane

A new approach for multiport network modeling (MNM) of multilayer planar circuits coupled through slots in ground plane is introduced. Generalized network formulation for aperture problems is combined with Okoshi's model for planar circuits to obtain a unified circuit model for two irregularly shaped planar circuits coupled through a slot of arbitrary shape in their common ground plane. The methodology, which can be generalized to structures having more than two layers, is described by applying the method to a two-layer structure. Results for several sample structures will also be presented     

Analysis of electromagnetic coupling through a thick aperture inmultilayer planar circuits using the extended spectral domain approachand finite difference time-domain method

Electromagnetic coupling plays a very important role in the design and development of integrated antenna arrays and microwave circuits. With the availability of accurate computer-aided design tools, proper characterization and analysis, this coupling phenomenon could be used to simplify the packaging and fabrication process, to reduce manufacturing cost, and also to add flexibility to the design of multilayer structures in many cases. An accurate and efficient spectral domain approach (SDA) is proposed as a means to study the coupling effect through an arbitrary aperture in a thick common ground plane of multilayer planar circuits. In addition, the finite difference time domain (FDTD) method is present as an alternate approach to this type of problem and also is used as a validation tool for the spectral domain method because of its simplicity, generality, and accuracy. The proposed methods are applied to different aperture coupled structures for illustration     

Effects on signal integrity and radiated emission by split reference plane on high-speed multilayer printed circuit boards

Power/ground partitioning has been used to supply multivoltage levels and to isolate power/ground noise in high-speed multilayer printed circuit boards. However, the partitioning of the power/ground plane breaks the current return path of the signal current through either the power plane or the ground plane, which causes undesired effects such as signal distortion, crosstalk, and radiation. To control and suppress these undesired effects, we should understand the electromagnetic mechanism associated with them. In this paper, the mechanism of the reflection and the transmission of the signal by the slotted power/ground plane is well understood through an analysis of measurements based on time-domain reflectometry. Considering the propagation of a slot wave through the slot line on the power/ground plane, we have successfully explained the changes of the transmitted and reflected waveforms. Furthermore, we have numerically and experimentally investigated the effects of the power/ground partitioning on the radiated emission in various structures. Finally, it is confirmed that the employment of a stitching capacitor on the power/ground slot suppresses the signal distortion and the radiated emission significantly. When the size and the location of the stitching capacitor are designed, there should be a compromise between the noise isolation and the guarantee of the return current path, with considering the resonance frequencies of planes by the capacitor.     

Excitation of Waveguide by Stripline- and Microstrip-Line-Fed Slots

This paper presents investigations on coupling between stripline/microstrip line and a rectangular waveguide coupled through a slot in the ground plane which is fixed in the cross-sectional plane of the waveguide. A closed-form expression for the impedance loading on stripline/microstrip line is evaluated from knowledge of the complex power flowing down the rectangular waveguide supporting the dominant mode and discontinuity in the modal voltage in stripline/microstrip line. The reactance cancellation is obtained by terminating the stripline/microstrip tine exciting the slot in a short-circuited stub. The structure under this condition forms a transition between stripline/microstrip line and a waveguide. The design curves on slot length versus frequency are presented for different values of dielectric constants. The variation of coupling as a function of frequency and also the location of the slot is evaluated. Numerical results for slot coupling useful for the design of waveguide simulators are also presented.     

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.     

Evaluation of edge effects in slot arrays using the geometricaltheory of diffraction

The geometric theory of diffraction (GTD) is applied to evaluate efficiently the coupling coefficient associated with the design of a waveguide-fed longitudinal shunt slot arrays. The coupling coefficient is proportional to the reaction integral between the field of a slot and the equivalent current distribution of another slot. Using an approximate form of the Green's function for the wedge, it is shown that the edge-diffraction field due to each slot is practically equal to the field of a suitable `mirror image' of such slot. In this way the actual coupling coefficient can be decomposed into a sum of coupling coefficients between slots on an infinite ground plane. The latter can be evaluated very efficiently so that inclusion of edge effects does not slow down the design procedure. The same approach also allows the computation of the relation between the self-admittance with and without the edge. Some test cases are provided which show that the overall error of this approximation can be neglected since it is comparable with the error due to mechanical tolerances     

Efficient analysis of microstrip-coupled nonradiative dielectric(NRD) resonators for hybrid integrated circuits

Nonradiative dielectric (NRD) resonators have been recently known as excellent stabilizing components for the design of a new class of oscillators based on hybrid integration of planar circuits and NRD-guides. However, an accurate characterization of such a component is needed in order to develop efficient computer-aided-design programs. In this paper, a hybrid planar integrated circuit comprising an NRD resonator is accurately modeled and is coupled to input and output planar microstrip circuits by means of long slots located on the top ground plane of the NRD structure. A reciprocity approach is used to solve the coupling problem between the resonator and microstrip lines. A modal expansion of the field equations has been applied to the NRD resonator in obtaining its rigorous field expressions. Finally, a transmission-line analysis is proposed for the structure, and scattering parameters have been calculated for different slot positions. Results are discussed for various parametric effects on coupling and Q-factor characteristics     

Coupling through narrow slot apertures to thin-wire structures

Electromagnetic coupling through a narrow slot aperture in an infinite ground plane is considered when a thin wire is present in the coupled half-space. The effect of the wire on coupling is determined. The slot has width and depth. The method of moments is applied to determine equivalent aperture currents and wire currents. Then coupling is calculated from the resulting fields. Results are presented for high and low Q slots and on and off resonance     

Coupling Between Microstrip Line and Image Guide through Small Apertures in the Common Ground Plane

A design theory is described for coupling between microstrip line and image guide through small coupling holes in a common ground plane. A five-slot Chebyshev coupler is designed based on coupling through a rectangular slot. The theoretical results are compared with experimental results.     

Achieving both wideband mitigation of ground bounce noise and good signal integrity by novel period structure

A double-square-ring slot period structure is proposed, designed in the power plane of the circuit board to suppress the ground bounce noise (GBN) in high-speed circuits. The novel design is based on the ring splits that connect the adjacent square patches in the power plane, which results in a wideband mitigation of the GBN ranging from 500 MHz to 5.5 GHz. The impact of the etched structures on the signal integrity (SI) is also investigated. Results show that good SI can be maintained while using the novel period structure in the power plane, and further improvement of the SI performance can be obtained by employing differential pairs of microstrip line for signals.     

Stripline to microstrip line aperture coupler

Aperture coupling between stripline and microstrip line is analyzed as a function of the electric and magnetic polarizabilities of the aperture, using Bethe's small-aperture coupling theory. A coupling expression for the general case of an aperture in the common ground plane is derived. Coupling variations with aperture dimensions for the case of a thin slot, a hole, a diamond, a rounded end slot, and an ellipse are determined using McDonald's polynomial approximations for the electric and magnetic polarizability for small apertures. Experimental results for the case of a thin slot and a circuit aperture are also presented