Closed-form expressions for transient power distribution network (PDN) noise caused by an IC switching current are derived for a PDN structure comprised of traces with decoupling capacitors. Criteria for identifying a dominant decoupling capacitor for an impulse switching current are also proposed. The derived PDN noise expressions are validated with measurements of currents at both local and bulk capacitors, the PDN impedance, and the total voltage noise in an operating consumer device.

Closed-Form Expressions for the Maximum Transient Noise Voltage Caused by an IC Switching Current on a Power Distribution Network

Numerical addition theorems of both axially anisotropic and axially isotropic parallel-plate modes are derived using a method based on boundary integral equations. This leads to a generalized multiple scattering (GMS) method for signal/power integrity analysis of dense vias in an arbitrarily shaped plate pair, which overcomes the limitation of the conventional multiple scattering method depending on the analytical addition theorems in an infinitely large or a finite circular plate pair. Both the numerical addition theorems and the GMS method have been validated by comparing results with either analytical expressions for special cases or full-wave simulations for more general cases. Several examples are provided to demonstrate the advantages of the generalized method over previous via models by taking into account the axially anisotropic modes due to the asymmetry caused by dense vias and/or arbitrarily shaped power/ground plate edges on via performance.

A Generalized Multiple Scattering Method for Dense Vias With Axially Anisotropic Modes in an Arbitrarily Shaped Plate Pair

A novel circular magnetic field probe is proposed, and measured results are presented. The proposed probe is easily fabricated by printing technology. A set of quasi-periodic notches was embedded into the connecting portion and acted as a microstrip filter. The experimental results indicate that the proposed probe effectively suppresses the inherent resonances of the circular loop, and the usable frequency range of the probe is broadened. In addition, measured magnetic field up to 9 GHz with the probe is presented to verify the performance of the probe. The measured magnetic and electric near-field in isolation and spatial resolution indicate that the proposed probe has advanced performance for near-field magnetic field detection compared with the conventional probe.

Printed magnetic field probe with enhanced performances

The China high-speed trains use cable trays to neatly arrange the cables running through the distributed systems. On one hand, they protect cables against external electromagnetic interference and reduce external radiation from the cables. On the other hand, the cable trays create waveguide structures that affect the coupling among cables inside the cable trays. To simplify coupling analysis for cables going through a cable tray, a lumped circuit model was built using admittance blocks extracted from a mixed-potential integral equation (MPIE) formulation. In the MPIE formulation, either the half-free space or the waveguide dyadic Green's function was used depending on the region where the cables were. A test case was investigated. Results by the proposed circuit model were validated by measurement and full-wave simulation results.

Coupling Analysis for Wires in a Cable Tray Using Circuit Extraction Based on Mixed-Potential Integral Equation Formulation

To measure the magnetic near field with high common-mode noise rejection, a probe with the differential and symmetrical structure forming a detection loop is developed. Such measurement is performed by using a two-port vector network analyzer (VNA) and validated by using a microstrip line as a device under test (DUT). In comparison to the measurement with traditional single-output magnetic near field probe, the electric field suppression of the proposed measurement can be improved by at least 10 dB in the frequency range of $3\sim 11$ GHz, while the other characteristics remain unchanged.

Magnetic Near-Field Measurement With a Differential Probe to Suppress Common Mode Noise

This paper documents the development, characterization, and application of a high-resolution thin-film magnetic-field probe. Probe diameter ranged from 5 mum to 100 mum. The 100 mum probe exhibits a 250 mum improvement in spatial resolution compared to a conventional loop probe, measured at a height of 250 mum over differential traces with a 118 mum spacing. Electric field rejection was improved using shielding and using a 180 degree hybrid junction to separate common-mode (electric field) and differential-mode (primarily magnetic field) coupling. A network analyzer with narrow band filtering was used to detect the relatively weak signal from the probe and to allow detection of phase information. An application of the probe is demonstrated where the probe is used to identify the magnitude and phase of magnetic fields produced by currents in very closely-spaced IC package pins.

/pdf/development-and-application-of-a-high-resolution-thin-film-vkuh9pu6kz.pdf

Development and Application of a High-Resolution Thin-Film Probe

Cavity model with segmentation method is extended to the analysis of radio frequency interference (RFI) problems in a shielding enclosure with printed circuit boards (PCBs) . Sixteen different Green's functions, instead of one in the conventional segmentation method developed for PCB cavities, are introduced to describe the fields in various cavities formed by enclosure walls and PCB copper planes. Both horizontal and vertical connections among these cavities are achieved by enforcing the boundary conditions along their common interfaces. Numerical examples demonstrate the efficiency and accuracy of the method by compared with full wave simulations.

https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=2575&context=ele_comeng_facwork

Efficient prediction of RF interference in a shielding enclosure with PCBs using a general segmentation method

A set of measurements has been performed on a test point source radiator. The near field, here assumed to be < 0.01 m, was measured with a near field scanning system using a simple magnetic loop probe and an electric field probe consisting of a small aperture truncated coax [1]. This paper develops the analysis of those measurements and shows that the two probes provide observation of specific components of the near radiated fields of a point source radiator when the magnetic component of the electric dipole equations and the electric component of the magnetic dipole equations are assumed to describe the radiation characteristics. This method of measurement and analysis is then applied to improving the RFI performance of a PC system clock device.

Measurement of a Point Source Radiator Using Magnetic and Electric Probes and Application to Silicon Design of Clock Devices

This paper presents an approach to obtain a flat frequency response from the first order derivative behavior of an electrically small loop and electrically short electric field probe by using them in combination with active oscilloscope probes. An H-field probe made in flex circuit technology was designed to operate up to about 5 GHz. These probes have loop dimensions as small as 3 × 3 mil and trace widths in the order of 1.75 mils. The H-field probe terminals are connected to the differential amplifier of the active oscilloscope probe which functions as an integrator to achieve a flat frequency response. The integrator behavior compensates for the first order derivative response of the flex circuit probes. The E-field probe utilizes the high input impedance of the browser attached to the active probe for achieving a flat frequency response.

Active probes for creating H-field probes for flat frequency response

A hybrid method is proposed for radio frequency interference (RFI) prediction of a metal enclosure with an aperture on the top wall. The structure is divided into several segments. While the fields in rectangular segments are described by cavity model, the segments with apertures are modeled by the commercial finite element solver (HFSS). Tangential field continuities along the common boundaries of different segments are enforced by the voltages and currents of boundary ports. Good agreement has been achieved between the hybrid method and full wave simulation.

/pdf/aperture-modeling-using-a-hybrid-method-for-rfi-analysis-3b91fmp7o4.pdf

Xiaopeng Dong

Papers

Development and Application of a High-Resolution Thin-Film Probe

Efficient prediction of RF interference in a shielding enclosure with PCBs using a general segmentation method

Measurement of a Point Source Radiator Using Magnetic and Electric Probes and Application to Silicon Design of Clock Devices

Active probes for creating H-field probes for flat frequency response

Aperture modeling using a hybrid method for RFI analysis