Printed Circuit Board Ground Research Articles

High gain D‐band hybrid integrated on‐chip antenna based on low‐cost printed circuit board packaging technology

AbstractA high gain D‐band hybrid integrated on‐chip antenna (OCA) based on a low‐cost printed circuit board (PCB) packaging technology is analyzed and designed in a standard 40‐nm CMOS process in this paper. The proposed OCA is a hybrid structure of a slotted patch OCA with off‐chip PCB ground and off‐chip dielectric resonator (DR). The proposed OCA exhibits a simulated gain of 3.5 dBi and 53% radiation efficiency at 150 GHz. The simulated impedance bandwidth is 20 GHz. The radiation performance and impedance bandwidth of the OCA are observably improved with the proposed techniques. The proposed OCA occupies 0.52 × 0.56 mm2, and addresses the highly desirable yet challenging overall design of future low‐cost integrated millimeter‐wave (mm‐Wave) and terahertz (THz) systems, which hit the mark on cost and compatibility.

Application of a Cavity Resonator Model for Characterization and Estimation of Radiation From a PCB–Chassis System

The electric far-field radiated from a printed circuit board (PCB)-chassis system is characterized using a cavity resonator model employing the far field calculated using an equivalent magnetic current loop. The inductive network method with measured current flowing through screws as a stimulus is used to calculate the frequency spectra of the electric field strength along the edge of the PCB with various locations of screws that connect the PCB ground to the chassis. Electric far fields from the equivalent magnetic current loop were derived using correction coefficients that incorporate the asymmetric dimensions of a parallel pair of PCB planes and the chassis. The calculation results reveal that the horizontal far field exceeds the vertical far field due to the asymmetric size coefficients and exhibit good agreement with the measurement results.

Improved band‐notch techniques for miniature UWB CPW‐fed slot antenna

ABSTRACTThis article describes a compact ultrawideband (UWB) antenna that exhibits desirable band‐notch and gain characteristics. The antenna consists of a rectangular aperture etched on a printed circuit board's ground plane that is excited by a rectangular‐shaped patch. It uses a novel technique comprising of open‐end stubs at the periphery of the ground in the vicinity of the feed‐line to improve its voltage standing wave ratio (VSWR) performance across the UWB. The proposed antenna uses three techniques to provide band‐notch function necessary to eliminate the wireless local‐area network interfering signals between 5 and 6 GHz. The frequency of the band‐notch characteristic can be tuned by varying the parameters defining the notch structure. The antenna was fabricated and its performance measured to validate its feasibility including the band‐notch techniques. A compact 19 × 19 mm2 antenna with aperture area of 9 × 18 mm2 was realized that exhibits an excellent VSWR performance and stable radiation patterns across the UWB spectrum. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:408–415, 2014

Calculation of Optimal Ground Post Resistance for Reducing Emissions from Chassis-Mounted Printed Circuit Boards

When a printed circuit board (PCB) is mounted to a metal chassis, the cavity formed between the circuit board ground and the chassis can resonate at certain frequencies resulting in unintended radiated emissions. The cavity resonances can be effectively suppressed by using conductive mounting posts and adding a resistance in series with the connection between one or more of these mounting posts and the PCB ground plane. This paper derives a simple closed-form expression for determining an optimal series resistance for damping these cavity resonances over a wide range of frequencies. This analysis was done for rectangular boards mounted on four posts located near the corners. A similar analysis could be done to determine the optimal resistance values for other board shapes and mounting post locations. For the four-post configuration, shorting one or more of the posts does not affect the optimum resistance value for the remaining posts.

Improved band-notch technique for ultra-wideband antenna

This study describes a compact ultra-wideband (UWB) antenna that exhibits desirable band-notch and gain characteristics. The antenna consists of a rectangular aperture etched on a printed circuit board's ground plane that is excited by a taper shaped patch. The antenna's broadband matching impedance is enhanced by inserting periodic open-end stubs (POES) on the inside edge of the rectangular aperture. A band-notch function to eliminate the WLAN interfering signals between 5 and 6 GHz is created on the proposed antenna using three different techniques. It is shown that the frequency of the band-notch characteristic can be tuned by varying the parameters of the notching structure. The antenna was fabricated and its performance measured to validate its feasibility and the band-notch techniques. A compact aperture area of 12×23 mm2 is realised which exhibits an excellent voltage standing wave ratio (VSWR) performance and stable radiation patterns over the UWB spectrum.

Isolation enhancement of planar disc antenna and ground plane in UWB applications

A technique is proposed to mitigate the unwanted effect of ground plane currents when an antenna is mounted on a printed circuit board (PCB). To demonstrate the concept a CPW fed monopole is integrated onto a relatively large PCB. In the first stage of integration, a microstrip to grounded CPW feedline is incorporated to avoid connecting the PCB and antenna ground directly. To reduce the flow of current onto the edges of the PCB, two pairs of quarter-wavelength stubs are then utilised. A prototype is manufactured and examined. To show how this method enhances the radiation characteristics, the radiation patterns of the antenna in both an isolated and an integrated scenario with and without stubs are compared.

Cavity Model for the Slot Radiation of an Enclosure Excited by Printed Circuit Board Traces With Different Loads

Traces on a printed circuit board (PCB) couple to the cavity consisting of the PCB ground plane and a metallic enclosure cover. We introduce this common-mode coupling of a PCB trace to the cavity field by an analytical model that is verified with 3-D simulations using HFSS. The cavity field causes radiated emission from the slots of the cavity. For an accurate calculation of the cavity field inside the enclosure and the radiated emission, we consider the radiation loss by a multiport approach. Comparisons of the analytical results for the radiated field to measurements show good agreement. Radiated emission can be calculated for arbitrary geometric enclosure shapes as a function of frequency, position of the trace on the PCB, and trace load/driver impedances.

Common-Mode Current Due to a Trace Near a PCB Edge and Its Suppression by a Guard Band

The common-mode (CM) current due to a trace near a printed circuit board (PCB) edge, and its suppression by a guard band have been studied experimentally and with finite-difference time-domain (FDTD) modeling. As the guard band, copper tape is connected along the entire edge of the ground plane. First, a PCB electromagnetic interference (EMI) coupling path that results from the nonzero impedance of the PCB ground plane is discussed. As the trace is moved closer to the PCB edge, the CM current increases. Then, the effect of the guard band on the CM current is detailed. A guard band parallel to and near a trace is most effective in suppressing the CM current. The cross-sectional magnetic field distribution at center of the PCB with and without the guard band is also calculated with FDTD modeling. The guard band decreases the magnetic field distributed on the reverse side of a PCB. These results indicate the guard band is effective in suppressing CM current. Finally, an empirical formula to quantify the relationship between the position of a trace and CM current for the case with a guard band is proposed. Calculated results using the empirical formula and FDTD modeling are in good agreement, which indicates this empirical formula should be useful for developing EMI design guidelines.

Measurement of the magnetic near field on a printed circuit board of finite size and a simple estimation method for far fields

Magnetic fields on the ground plane of a printed circuit board (PCB) are focused with consideration of the currents on it. The field distribution on the upper side (substrate side) and lower side of a PCB with a finite ground area are considered experimentally. The electric far field radiated from the PCB is measured and compared with calculated results, based on measuring edge currents. The experimental results show that a common-mode current causes larger magnetic fields on the under side of the PCB ground plane than on the upper side, and also a large electric far field. © 1998 Scripta Technica. Electron Comm Jpn Pt 1, 81(1): l4–21, 1998

Measurement of the magnetic near field on a printed circuit board of finite size and a simple estimation method for far fields

Magnetic fields on the ground plane of a printed circuit board (PCB) are focused with consideration of the currents on it. The field distribution on the upper side (substrate side) and lower side of a PCB with a finite ground area are considered experimentally. The electric far field radiated from the PCB is measured and compared with calculated results, based on measuring edge currents. The experimental results show that a common-mode current causes larger magnetic fields on the under side of the PCB ground plane than on the upper side, and also a large electric far field. © 1998 Scripta Technica. Electron Comm Jpn Pt 1, 81(1): l4–21, 1998