Four-corner snakelike bridge broadband electromagnetic band gap structure

Abstract

The invention discloses a four-corner snakelike bridge broadband electromagnetic band gap structure, and belongs to the technical field of circuit microwaves. According to the structure, complementary split-ring resonator shape etching is carried out at the center, and the snake-shaped bridge structures are arranged between the adjacent units, so that the inductance between the electromagnetic band gap units is increased, low-frequency-band SSN is effectively suppressed, the bandwidth is relatively wide, and SSN of a stop band can be effectively suppressed. The four sides of the EBG structure are etched into rectangles, and adjacent elements are connected to form a bridge. Compared with a traditional L-bridge structure, the S-shaped structure is designed, so that the surface current path can be increased, and the equivalent inductance and the equivalent capacitance are increased. The gap between the resonant rings generates a gap current and generates a resonant circuit, so that the cut-off frequency can be effectively reduced and the width of a stop band can be improved. The ultra-wide band gap structure takes the suppression depth of-30dB as a standard, can reach an ultra-wide band gap of 23.8 GHz, is obviously superior to a conventional electromagnetic band gap structure, and can better suppress the noise of a synchronous switch.

Description

Technical Field

[0001] The invention relates to a four-corner serpentine bridge broadband electromagnetic band gap structure, which belongs to the technical field of circuit microwaves. Background Art

[0002] In recent years, high-impedance surfaces constructed by EBG structures have become a new method to suppress high-frequency SSN (simultaneous switch noise). The EBG structure was first introduced by Yablonovitch and Jonh. Experts proposed mushroom-type EBG structures and coplanar EBG structures to suppress the propagation of power noise in high-density integrated system packaging circuits. Several common coplanar EBG structures are: uniplanar-compact EBG (UC-EBG) structure, L-bridge EBG (L-bridge EBG) structure, alternating impedance EBG (Al-EBG) structure. The coplanar EBG structure has also evolved into a microstrip interconnected EBG structure, a broken line coplanar EBG structure, etc. The coplanar EBG structure adopts the advantages of standard PCB manufacturing technology, does not require special design of vias and the use of multiple metal layers, and breaks through the design bottleneck of the mushroom EBG structure that requires drilling and the use of multiple metal layers.

[0003] As the functions and component integration of integrated circuit (IC) system-in-package (SIP) continue to increase, electromagnetic coupling and parasitic phenomena in the interconnection network are also growing rapidly, which in turn exacerbates the noise problems in the power distribution network and signal path. Among them, with the rapid increase in signal edge rise and fall rates, clock frequencies and signal transmission rates, the synchronous switching noise in the power supply network is becoming more and more significant, posing a threat to the power supply quality and signal quality, and becoming the main problem faced by SIP power integrity and signal integrity design. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a four-corner serpentine bridge wide-band electromagnetic bandgap structure, aiming to design a miniaturized wide-band electromagnetic bandgap structure to solve the power integrity problem caused by synchronous switching noise in system-level packaging.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a four-corner serpentine bridge wide-band electromagnetic bandgap structure, characterized in that: a complementary open resonant ring is arranged at the center of the device body, four groups of serpentine bridge structures are arranged in a clockwise direction on the four corners of the device body, the serpentine bridge structure adopts a serpentine bridge straight edge and a serpentine bridge serpentine edge, the two ends of the serpentine bridge straight edge are a straight edge connecting end and a straight edge extending end, the serpentine bridge serpentine edge adopts a concave-convex broken line structure, and the two ends are a serpentine edge connecting end and a serpentine edge free end;

[0006] The straight side connecting end of the serpentine bridge straight side is connected to the device body, and a straight side body gap is set between the serpentine bridge straight side and the device body; the straight side extending end is connected to the serpentine side connecting end of the serpentine side of the serpentine bridge; the serpentine side of the serpentine bridge is set on the outer side of the serpentine bridge straight side in the next group of serpentine bridge structures in a clockwise direction.

[0007] Furthermore, the side length of the structure is L1=30 mm, the line width of the serpentine edge of the serpentine bridge is L2=0.2 mm, the width of the concave and convex fold line groove of the serpentine edge of the serpentine bridge is L3=0.8 mm, the depth of the concave and convex fold line groove of the serpentine edge of the serpentine bridge is L4=1.425 mm, the distance from the concave edge of the fold line groove of the serpentine edge of the serpentine bridge to the straight edge of the serpentine bridge is L5=0.85 mm, the line width of the straight edge of the serpentine bridge is L6=0.525 mm, the width of the gap between the straight edge body is L7=0.3 mm, L8=3.45 mm, and L9=0.3 mm.

[0008] The four-corner serpentine bridge wide-band electromagnetic bandgap structure array adopts the above four-corner serpentine bridge wide-band electromagnetic bandgap structure to form an array, the number of arrays in the length direction of the array is at least 2, and the number of arrays in the width direction of the array is at least 2.

[0009] Furthermore, the array uses serpentine edges of serpentine bridges between adjacent electromagnetic bandgap structures to be interconnected.

[0010] Furthermore, the array is connected to each other by using the folded line grooves and convex edges of the serpentine edges of the serpentine bridges between adjacent electromagnetic band gap structures.

[0011] The key point of this structure is to etch a snake-shaped bridge structure similar to an L-bridge at the four corners of the square patch, and etch a complementary split-ring resonator (CSRR) shape in the center. The snake-shaped bridge structure between adjacent units increases the inductance between the electromagnetic bandgap units, effectively suppresses the SSN in the low-frequency band, has a relatively wide bandwidth, and can effectively suppress the SSN in the stop band. On the basis of the L-bridge structure, a snake-shaped structure is added. The corresponding dimensions are l1=30 mm, l2=0.2 mm, l3=0.8 mm, l4=1.425 mm, l5=0.85 mm, l6=0.525 mm, l7=0.3 mm, l8=3.45 mm, l9=0.3 mm. The four sides of the EBG structure are etched into rectangles, and adjacent elements are connected to form a bridge.

[0012] The beneficial effects of the present invention are as follows: compared with the conventional coplanar structure and the EBG structure proposed in other documents, the present invention etches a complementary split-ring resonator (CSRR) shape in the center, and increases the inductance between the electromagnetic bandgap units with a serpentine bridge structure between adjacent units, effectively suppresses the SSN in the low-frequency band, has a relatively wide bandwidth, and can effectively suppress the SSN in the stopband. The four sides of the EBG structure are etched into a rectangle, and the adjacent elements are connected to form a bridge. Compared with the traditional L-bridge structure, the surface current path can be increased by designing this serpentine structure, thereby increasing the equivalent inductance and equivalent capacitance. At the same time, the CSRR is etched in the inner center of the unit structure. The gap between the resonant rings will generate a gap current and a resonant circuit, which can effectively reduce the lower cutoff frequency and improve the width of the stopband.

[0013] The electromagnetic suppression frequency band range of the novel EBG structure of the present invention is greatly expanded. When the suppression depth is -30dB, it can effectively cover 2.7GHz~26.5GHz, realizing effective suppression of SSN in high-density integrated system packaging circuits. Compared with the reference board, when the suppression depth is -30dB, the stopband range of the traditional L-bridge EBG structure in 0-10GHz is 0.38GHz to 7.5GHz. The stopband range of the EBG structure in the present application is 2.7GHz to 26.5GHz, which is much larger than the traditional structure. Signal integrity is mainly measured by eye diagrams, and the quality of eye diagrams is measured by maximum eye height (MEO) and maximum eye width (MEW). Generally speaking, the larger the MEO and MEW, the better the eye diagram quality and the better the time domain transmission characteristics of the signal line. In order to improve the quality of the received signal, differential line pairs are used to transmit signals. Differential pairs can reduce the coupling of transmission lines. Compared with single-ended lines, the MEO of the differential line output mode increases by 30.8%, the MEW remains almost unchanged, and the signal integrity problem is significantly improved.

[0014] Aiming at the power integrity problem caused by synchronous switching noise in high-density integrated system-level packaging, a new electromagnetic bandgap structure is designed. The structure is formed by a complementary open resonant ring unit structure and a snake-shaped inter-unit bridge structure. The rectangle is etched to reduce the effective capacitance of the patch, and the length-to-width ratio of the bridge is increased to increase the effective inductance of the patch. The proposed structure is modeled and simulated using the electromagnetic full-wave simulation software HFSS. The simulation results show that with a suppression depth of -30dB as the standard, an ultra-wide bandgap of 23.8GHz can be achieved, which is significantly better than the conventional electromagnetic bandgap structure and can better suppress synchronous switching noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 This is a novel EBG structure diagram of the present invention.

[0017] Figure 2 Insertion loss plots of the new EBG simulation, measurement, and reference boards.

[0018] Figure 3 is a simulated eye diagram of a reference board using a single-ended signal.

[0019] Figure 4 This is a simulated eye diagram of an EBG board using a single-ended signal.

[0020] Figure 5 This is a simulated eye diagram using an EBG board with differential signals.

[0021] Figure 6 This is a schematic diagram of the new 2*2 array EBG and simulation port.

[0022] Figure 7 It is an EBG structure and measurement device.

[0023] Figure 8 It is a single-ended and differential transmission line structure: the left picture in the figure is a single-ended transmission line structure, and the right picture is a differential transmission line structure.

[0024] In the figure: 1, device body, 2, complementary open resonant ring, 3, serpentine bridge straight edge, 4, serpentine bridge serpentine edge, 4a, concave and convex zigzag groove, 4b, convex edge of zigzag groove, 4c, concave edge of zigzag groove, 5, straight edge connecting end, 6, straight edge protruding end, 7, straight edge body gap, 8, serpentine edge connecting end, 9, serpentine edge free end. DETAILED DESCRIPTION

[0025] The key design point of the new EBG structure proposed in this patent is to etch an L-bridge-like serpentine bridge structure at the four corners of the square patch and etch a complementary split-ring resonator (CSRR) shape in the center. The serpentine bridge structure between adjacent units increases the inductance between the electromagnetic bandgap units, effectively suppresses SSN in the low-frequency band, has a relatively wide bandwidth, and can effectively suppress SSN in the stop band. Figure 1 The proposed novel EBG structure is shown. A four-corner serpentine bridge wide-band electromagnetic bandgap structure, a complementary open resonant ring 2 is arranged at the center of the device body 1, four groups of serpentine bridge structures are arranged clockwise on the four corners of the device body 1, the serpentine bridge structure adopts a serpentine bridge straight edge 3 and a serpentine bridge serpentine edge 4, the two ends of the serpentine bridge straight edge 3 are a straight edge connecting end 5 and a straight edge extending end 6, the serpentine bridge serpentine edge 4 adopts a concave-convex broken line structure, and the two ends are a serpentine edge connecting end 8 and a serpentine edge free end 9;

[0026] The straight side connecting end 5 of the serpentine bridge straight side 3 is connected to the device body 1, and a straight side body gap 7 is set between the serpentine bridge straight side 3 and the device body 1; the straight side extending end 6 is connected to the serpentine side connecting end 8 of the serpentine bridge serpentine side 4; the serpentine bridge serpentine side 4 is set on the outer side of the serpentine bridge straight side 3 in the next group of serpentine bridge structures in a clockwise direction.

[0027] In some specific embodiments, a four-corner serpentine bridge wide-band electromagnetic bandgap structure array is formed by using the above-mentioned four-corner serpentine bridge wide-band electromagnetic bandgap structure, and the number of arrays in the length direction of the array is at least 2, and the number of arrays in the width direction of the array is at least 2.

[0028] In some embodiments, the arrays are interconnected using serpentine bridges 4 between adjacent EBG structures.

[0029] In some specific embodiments, the arrays are connected to each other using the folded groove convex edges 4b of the serpentine edges 4 of the serpentine bridges between adjacent electromagnetic bandgap structures.

[0030] On the basis of the L-bridge structure, a serpentine structure is added. The side length of the structure is L1 = 30 mm, the line width of the serpentine side of the serpentine bridge is L2 = 0.2 mm, the width of the concave and convex folding line groove of the serpentine bridge serpentine side is L3 = 0.8 mm, the depth of the concave and convex folding line groove of the serpentine bridge serpentine side is L4 = 1.425 mm, the distance from the concave side of the serpentine bridge serpentine side folding line groove to the straight side of the serpentine bridge is L5 = 0.85 mm, the line width of the straight side of the serpentine bridge is L6 = 0.525 mm, the width of the straight side body gap is L7 = 0.3 mm, the internal complementary resonant ring diameter is L8 = 3.45 mm, and the ring width is L9 = 0.3 mm. The four sides of the EBG structure are etched into rectangles, and adjacent elements are connected to form a bridge. Compared with the traditional L-bridge structure, the surface current path can be increased by designing this serpentine structure, thereby increasing the equivalent inductance and equivalent capacitance. At the same time, CSRR is etched in the inner center of the unit structure. The gap between the resonant rings will generate gap current and produce a resonant circuit, which can also reduce the lower cutoff frequency and improve the width of the stop band.

[0031] Compared with conventional coplanar structures and EBG structures proposed in other literatures, the electromagnetic suppression frequency band of the novel EBG structure in the present invention is greatly expanded. When the suppression depth is -30dB, it can effectively cover 2.7GHz~26.5GHz, thus achieving effective suppression of SSN in high-density integrated system packaging circuits. Figure 7 The vector network analyzer (Agilent Technologies N5252APNA-X) measures S21, and the results are as follows Figure 2 shown. Figure 2 The insertion loss of the new EBG simulation, measurement, and reference board is shown. Compared with the reference board, the stopband range of the traditional L-bridge EBG structure in 0-10GHz is 0.38GHz to 7.5GHz when the suppression depth is -30dB. The stopband range of the new EBG structure is 2.7GHz to 26.5GHz, which is much larger than the traditional structure. Figure 2 As shown, the measured results are basically consistent with the simulation results. Since the experimental conditions cannot completely restore the simulation conditions, the small error between the simulation results and the measured results is acceptable. Signal integrity is mainly measured by the eye diagram, and the quality of the eye diagram is measured by the maximum eye height (MEO) and the maximum eye width (MEW). Generally speaking, the larger the MEO and MEW, the better the eye diagram quality and the better the time domain transmission characteristics of the signal line. Eye diagram simulation results of a complete power ground plane and a power ground plane structure etched with an EBG structure: Figure 3 The MEO of a complete power plane with single-ended transmission signals is 794mV and the MEW value is 285.3ps. Figure 4The eye diagram of the signal integrity in the new EBG power plane when using a single-ended line to transmit the signal is shown, with an MEO value of 652mV and a MEW value of 280ps. In order to improve the quality of the received signal, a differential line pair is used to transmit the signal. The differential pair can reduce the coupling of the transmission line. Figure 5 The eye diagram of signal integrity in the new EBG power plane for differential line pairs is shown, with an MEO value of 853mV and a MEW value of 279.4ps. Compared with single-ended lines, the MEO of the differential line output mode increased by 30.8%, and the MEW remained almost unchanged, and the signal integrity problem was significantly improved.

[0032] Figure 6 Schematic diagram of the new 2*2 array EBG and simulation ports, i.e. the transmission coefficient S21 between port 1 and port 2. Figure 5 The upper left corner of the plate structure is the origin of the coordinates, and two lumped ports are set, port 1 (15mm, 15mm) is set as the input port, and port 2 (45mm, 45mm) is set as the output port. The insertion loss is obtained by simulation, that is, the transmission coefficient S21 between port 1 and port 2. Figure 8 For single-ended and differential transmission line structures, a four-layer PCB (signal layer, power layer, ground layer, signal layer) is used to study its signal integrity performance. Figure 8 As shown in the figure, a 1mm thick FR4 dielectric material is used between the boards, and the characteristic impedance of the signal transmission line is 50Ω. The signal line passes through the through hole from the top layer, enters the bottom layer, and returns to the top layer through the signal trace and the second through hole of the bottom layer, so as to experiment the signal integrity of the new EBG structure.

Claims

1. A four-corner serpentine bridge broadband electromagnetic bandgap structure, characterized in that: A complementary open resonant ring (2) is arranged at the center of the device body (1), and four groups of serpentine bridge structures are arranged in a clockwise direction at the four corners of the device body (1), the serpentine bridge structure adopts a serpentine bridge straight edge (3) and a serpentine bridge serpentine edge (4), the two ends of the serpentine bridge straight edge (3) are a straight edge connecting end (5) and a straight edge extending end (6), and the serpentine bridge serpentine edge (4) adopts a concave-convex fold line structure, and the two ends are a serpentine edge connecting end (8) and a serpentine edge free end (9); The straight edge connection end (5) of the serpentine bridge straight edge (3) is connected to the device body (1), and a straight edge body gap (7) is arranged between the serpentine bridge straight edge (3) and the device body (1); the straight edge extension end (6) is connected to the serpentine edge connection end (8) of the serpentine bridge serpentine edge (4); the serpentine bridge serpentine edge (4) is arranged on the outside of the serpentine bridge straight edge (3) in the next group of serpentine bridge structures in a clockwise direction.

2. The four-corner serpentine bridge broadband electromagnetic bandgap structure according to claim 1, characterized in that: The side length of the structure is L1=30 mm, the line width of the serpentine edge of the serpentine bridge is L2=0.2 mm, the width of the concave and convex fold line groove of the serpentine edge of the serpentine bridge is L3=0.8 mm, the depth of the concave and convex fold line groove of the serpentine edge of the serpentine bridge is L4=1.425 mm, the distance from the concave edge of the serpentine edge groove of the serpentine bridge to the straight edge of the serpentine bridge is L5=0.85 mm, the line width of the straight edge of the serpentine bridge is L6=0.525 mm, the width of the gap between the straight edge body is L7=0.3 mm, the diameter of the internal complementary resonant ring is L8=3.45 mm, and the ring width is L9=0.3 mm.

3. A four-corner serpentine bridge broadband electromagnetic bandgap structure array, characterized in that: The four-cornered serpentine bridge wide-band electromagnetic bandgap structure described in claim 1 or 2 is used to form an array, and the number of arrays in the length direction of the array is at least 2, and the number of arrays in the width direction of the array is at least 2.

4. The four-corner serpentine bridge broadband electromagnetic bandgap structure array according to claim 3, characterized in that: The array is connected to each other by using serpentine bridges and serpentine edges (4) between adjacent electromagnetic band gap structures.

5. The four-corner serpentine bridge broadband electromagnetic bandgap structure array according to claim 4, characterized in that: The array is connected to each other by using the folded groove convex edges (4b) of the serpentine edges (4) of the serpentine bridges between adjacent electromagnetic band gap structures.

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