Circuit Board Having Shielding Planes with Varied Void Opening Patterns for Controlling the Impedance and the

Transmission Time of Differential Transmission Lines

Chi-Kuang HwangDept. of Electrical EngineeringChung-Hua University

Patents

Inventors– Gwun-Jin Lin– Chi-Kuang Hwang– Ching-Cheng Tien

USA (4) Japan Korea Europe Taiwan China

Introduction

Structure – Shielding Planes– Varied Void Opening Patterns– Controlling the Impedance and the Transmission Time– Differential Transmission Lines

Differential Transmission Lines– High Frequency Transmission Rate (Differential Transmission

Lines)– High Noise Rejection capability– Low EMI– Low Voltage

Characteristic Impedance

Coaxial Cable

)ln(276

0 a

DZ

r

)ln(138

)ln(2

10 a

b

a

b

C

LZ

r

• Two-Wire Transmission Line

D

ab

Impedance Matching

Common mode 50Ω

Differential Mode 100 Ω

Virtual Ground

Slow Wave Effect

Solid Ground – Fast Transmission Time

Void Opening Pattern– Slow Transmission Time

Similar to 100m Race with or without Hurdles

Mechanical Properties

Symmetric– Fatigue Test (20000 Times)

4000 Times (Taiwan) 7000 Times (Japan) 40000 Times

Manufacturing– Single Layer Double Access

Figure 1

Figure 2

Figure 3

Flexible material

Adhesive

Solder masker

Adhesive

Z

82

84

82 82

60 6264

6668

708484

4040

2828 Solder masker

Flexible material

28

2882

82 28

40

40 844084

Conducting element

Y

Figure 4

Figure 5

Flexible material

Adhesive

Solder masker

Adhesive

Z

82

64 6668

708440(74)

28(72) Solder masker

Flexible material

28

40

54

X

50

Figure 6

Figure 7

Figure 8

Z

96

94

9290

162 98 100

120164

160

164140 140 140160 162

120 120

Y

160

120162

Flexible material

Adhesive

Solder masker

Adhesive

Solder masker

Flexible material

120

140

Conducting element

162160140

Figure 9

Figure 10

260

1111

X

Y

262242 244 242 244242 244

264 266

242 244268

270

232

230

220240

250

224 224 224 224222

222222 222

Figure 11

X

Z270260

240262

264

240

266

268

220220220

250

250250

250250

220250 250 250 250 250

Flexible material

Adhesive

Solder masker

Adhesive

Solder masker

Flexible material

Conducting element

220

240

Figure 12

Figure 13

X

Z

220(272)220264

266

220268270

240(274) 240

240

250 250

220

54

Flexible material

Adhesive

Solder masker

Adhesive

Solder masker

Flexible material

Conducting element

220

250240 240

250 250 250 250240

Figure 14

Figure 15

X

Y

290 292

324

322 294 296

328

326

332330298 300

340

320

352350348346344

342354

356 358

1616

Figure 16

Flexible material

Adhesive

Solder masker

Adhesive

Z 354

354

290 292

320 Solder masker

Flexible material

320

340

340

Conducting element

320320 320354

356 358

358

354

340

294296

356340

340

358

298 300358

X

Figure 17

18

372

Pairs of differential mode

Gound for DC power (54)

DC power (88)

Figure 18

452450448446444

442464

462460

400

380

432428

366

364390

424422

362

360 426392

430

368

370

19 19

Figure 19

Flexible material

Adhesive

Solder masker

Adhesive

Z400

460

360

362

380 Solder masker

Flexible material

380

400

400

Conducting element

400

390

364

366400 462

392400368 370

464

460

380

460 460

380 390 380 380 392

462 462 462 464

460 460

462

462

X

Applications

Computers and Communications– Notebook– Cellular Phone– PDA

Display– LCD

Testing Cables

Connectors Testing Cables Standard Cables Non-Adhesive Flexible Cables

– Chip On Film (COF)

Single Layer Double Access