本論文首先討論測試場地接地面對混合式天線(雙錐式對數週期偶極陣列天線)之天線因子的影響。同時，天線與接地面的互耦情形、以及工作相位中心的變動也一併被探討。根據這些分析，本論文提出一種結合改良式標準場方法(SSM)和相位中心與場型匹配法(PCPM)，藉此可以取得混合天線之受場地低度影響的天線因子，進而計算出較為合理之正規化場地衰減值。
其次，本論文提出一種簡單、快速、和準確的方法，可用來校正寬頻電磁相容天線之自由空間天線因子。此法採用一種固定高度的量測架構，以及一種多重信號分類(MUSIC)法則的演算法。這種量測架構可以大幅縮短量測時間，並且可避免因不同量測高度所產生的校正誤差。同時，多重信號分類(MUSIC)法則之演算法，可以排除來自接地面或其他反射物所反射之非預期信號，藉此可以計算出自由空間之天線因子。此外，本演算法也自動補償相位中心的偏移，使得量測更加容易和方便。在本方法的驗證方面，校正量測的結果皆與其他現行的標準方法做比較。在對數週期偶極陣列天線、混合式天線、以及對雙脊喇叭天線的量測比較，其平均誤差分別低於0.25 dB、0.42 dB和0.36 dB。
最後，本論文也提出一種從三個自耦合電感的兩端導入兩個等效負電感的方法，藉此有效降低典型三電容式電磁干擾濾波器之寄生電感。本文除進行此方法之理論分析和公式推導外，也針對一組三電容式電磁干擾濾波器進行實驗量測，結果顯示本方法可以降低其在頻率50 MHz之差模輸入損失約16.8 dB和共模輸入損失約19.2 dB。
在本文的附錄A，收錄一項有關接地面對天線輻射影響的延伸研究，本研究在單極天線之有限接地面的邊緣設計V型溝槽，藉此可以降低天線場型的漣波。這種V型結構的最佳設計可以將場型漣波的峰對峰值從26 dB降低至4.5 dB。

This thesis first discusses the ground plane effects of a test site on the antenna factors (AFs) of hybrid antenna (biconical log-periodic dipole array). Meanwhile, the effects of mutual coupling between antenna and its image, and the variation of active phase center are also discussed. From these analyses, a hybrid method, based on the modified SSM (Standard Site Method) and the PCPM (Phase Center and Pattern Matching) applied to the hybrid antenna for NSA (Normalized Site Attenuation) measurement is proposed. By this method, the low geometry- dependent AFs of hybrid antenna can be obtained to produce more reasonable NSA values for a test site.
Secondly, this thesis proposes a simple, fast, and accurate method to calibrate the free-space AFs of broadband EMC (Electromagnetic Compatibility) antennas. This method adopts a fixed-height configuration and a MUSIC (MUltiple SIgnal Classification) algorithm. This configuration significantly shortens measurement time and removes height-dependent calibration errors. Meanwhile, the MUSIC algorithm can remove unexpected reflections from the ground plane or any other reflecting objects, by which the free-space AFs can be calculated. In addition, this method can also automatically compensate for the phase center shift, which makes measurement easier and more convenient. To verify this method, the calibrated results are compared with other published standard methods: the mean differences can be as low as 0.25 dB for the LPDA (log-periodic dipole array), 0.42 dB for the hybrid antennas, and 0.36 dB for the horn antennas.
Finally, this thesis provides a method of using two equivalent negative inductances from two terminals of three coupled inductors to reduce the parasitic inductances of a typical three-capacitor EMI (Electromagnetic Interference) filter. Theoretical analysis and formula deduction for the design of two equivalent negative inductances are demonstrated. The experimental results show that the insertion losses of a three-capacitor EMI filter at 50 MHz can be reduced by 16.8 dB for the DM (differential-mode) and by 19.2 dB for the CM (common-mode).
In Appendix A of this thesis, an extended study of the effect of ground plane on antenna’s radiation is described. A simple V-shape edge-groove design for a finite ground plane can effectively reduce the pattern ripples of a monopole. The optimal design of proposed structure can reduce the peak-to-peak pattern ripples from 26 to 4.5 dB.

誌 謝 ……………………………………………………………...……………… I
摘 要 …………………………………………………………………………….. II
Abstract …………………………………………………………………………… III
Contents …………………………………………………………………………...... V
List of Figures …………………………………………………………………… VIII
List of Tables ……………………………………………………………………. XII
Glossary of abbreviations ………………………………………………………. XIII
Chapter 1 Introduction …………………………………………………………... 1
1.1 Background and motivations ……………………………………………... 1
1.1.1 Hybrid antennas for NSA measurements …………………………… 1
1.1.2 Free-space antenna factor measurements …………………………... 3
1.1.3 Parasitic inductances of a three-capacitor EMI filter ………………..7
1.2 Outline of the thesis ……………………………………………………..... 9
Chapter 2 Application of hybrid antennas in NSA measurements…...………. 11
2.1 Analysis of antenna factor of hybrid antenna…………………………….. 11
2.1.1 Numerical model of a hybrid antenna …..………………………… 11
2.1.2 Ground effect on antenna factor …..………………………………. 13
2.1.2.1 Non-uniform incident field …………………………………....15
2.1.2.2 Mutual coupling with ground plane ……………………….…. 17
2.1.3 Phase center correction …………………….……………………... 19
2.2 The PCPM method ………………………………………………………. 23
2.3 Calibration of hybrid antennas by the PCPM ……………………………. 25
2.4 The SSM with measured distance compensation …………………………34
2.5 The differences in NSA measurement between tuned dipoles and hybrid antennas ………………………………………………………………….. 35
Chapter 3 An improved method for free-space antenna factor measurements …...……………………………………………………… 43
3.1 Calibration configuration and data processing algorithms ………………. 43
3.1.1 Geometry and algorithms …………….......……………………….. 43
3.1.2 Spatial smoothing preprocessing ………………………………….. 46
3.1.3 MUSIC algorithm with the SSP …………………………………... 48
3.1.4 Free-space transmission model …………………………………… 53
3.2 Simulation for half-wave dipoles ……………………………………….... 55
3.3 Experimental measurements …………………………………………….. 56
3.3.1 LPDA antennas ……………………………………………………. 57
3.3.2 Hybrid antennas …………………………………………………... 60
3.3.3 Double-ridged horn antennas ……………………………………... 61
Chapter 4 A method to reduce parasitic inductances of a three-capacitor EMI filter ………………………………………………………………….. 63
4.1 Two equivalent negative inductances in three coupled inductors ….……. 63
4.2 Parasitic inductance reduction for a three-capacitor EMI filter ….……… 67
4.3 Simulations and measurements ………………………….………………. 71
4.4 Sensitivity analysis ……………………………………….……………… 76
4.4.1 Variations of L1, L2, L3 …………………………….………………. 76
4.4.2 Variations of M12, M23, M13 ……………………….………………. 79
4.4.3 Summary of parameter variations ……………….………………... 83
Chapter 5 Conclusions ………………………………………………………….. 84
Appendix A A V-shape edge-groove design for a finite ground plane to reduce pattern ripples of a monopole ……………...……………………... 86
A.1 Background and motivations …………………………………………… 86
A.2 Design of the V-shape edge-groove edge ……………………………….. 87
A.3 Results and discussions …………………………………………………. 88
A.4 Summary ………………………………………………………………... 94
Appendix B NSA theory and measurement …………………………………… 95
B.1 Theoretical NSA………………………………………….……………… 95
B.1.1 Far electric field in free space…………………………………….. 95
B.1.2 Electric field of horizontally polarized half-wave dipoles………... 98
B.1.3 Electric field of vertically polarized half-wave dipoles ………… 100
B.1.4 Formulation of NSA …………………………………………….. 102
B.2 Procedures of NSA measurement……….……………………………… 103
Appendix C Standard site method ……………………………………………. 106
Bibliography ……………………………………………………………………... 109
Publication list …………………………………………………………………… 114

List of Figures
Figure 1.1 First-order equivalent circuit of a capacitor ……………………………… 8
Figure 2.1 Numerical model of a hybrid antenna …………………………………... 11
Figure 2.2 Simulated horizontal AF using the standard site method ……………….. 14
Figure 2.3 Simulated vertical AF using the standard site method ………………….. 14
Figure 2.4 Field uniformity at d=3,4,5,10,50,and 100m distance along a 1.35m line at the boresight of a vertical point dipole placed 2m height above a PEC ground plane …………………………………………………………….. 16
Figure 2.5 AF variation versus distance when the receive vertical hybrid antenna is placed at d=3,4,5,10,50, and 100m away from two point dipoles that emulating a vertical point dipole above a PEC ground plane …………… 16
Figure 2.6 Input impedance variation (%) of a horizontal biolg antenna at different heights above a PEC ground …………………………………………….. 18
Figure 2.7 AF variation versus height for a horizontal hybrid placed above a PEC ground plane …………………………………………………………….. 19
Figure 2.8 Phase center of the hybrid antenna ……………………………………... 20
Figure 2.9 Simulated horizontal AF with phase center correction …………………. 21
Figure 2.10 Horizontal AF error of phase center correction ……………………….. 21
Figure 2.11 Simulated vertical AF with phase center correction …………………... 22
Figure 2.12 Vertical AF error of phase center correction …………………………... 22
Figure 2.13 Calculation model of a received electric field for PCPM …..…………. 24
Figure 2.14 Geometric dimensions of two hybrid antennas …..……………………. 27
Figure 2.15 AF of Antenna I using the SSM ………..……………………………… 28
Figure 2.16 AF of Antenna II using the SSM …..…………………………………... 28
Figure 2.17 Maximum AF variations of Antenna I using SSM and PCPM ……..…. 30
Figure 2.18 Maximum AF variations of Antenna II using SSM and PCPM ……..… 30
Figure 2.19 Current distributions of Antenna I at the frequency of 260 MHz …..…. 31
Figure 2.20 Radiation Pattern of Antenna I at the frequency of 260 MHz …..…….. 31
Figure 2.21 Measured field and Ec of Antenna I for h1 = 1 m, R = 3 m at 260 MHz ……………………………………………………………………... 32
Figure 2.22 Measured field and Ec of Antenna I for h1 = 1 m, R = 3 m at 600 MHz ……………………………………………………………………... 32
Figure 2.23 Measured field and Ec of Antenna I for h1 = 1 m, R = 3 m at 1 GHz …. 33
Figure 2.24 Maximum AF variations of Antenna I using the SSM_mdc …………... 34
Figure 2.25 Maximum AF variations of Antenna II using the modified SSM ……... 34
Figure 2.26 NSA measurement at h1=2m, R=3m, horizontal polarization ………… 37
Figure 2.27 NSA measurement at h1=2m, R=10m, horizontal polarization ……….. 37
Figure 2.28 Deviation of NSA by ANSI C63.4 at h1=2m, R=3m, horizontal polarization ……………………………………………………………… 38
Figure 2.29 Deviation of NSA by ANSI C63.4 at h1=2m, R=10m, horizontal polarization ……………………………………………………………… 38
Figure 2.30 CFNSA (modified) at h1=2m, R=3m, horizontal polarization ………… 40
Figure 2.31 CFNSA (modified) at h1=2m, R=10m, horizontal polarization ……….. 41
Figure 2.32 Deviation of NSA (CFNSA) at h1=2m, R=3m, horizontal polarization.. 41
Figure 2.33 Deviation of NSA (CFNSA) at h1=2m, R=10m, horizontal polarization ……………………………………………………………… 42
Figure 3.1 Geometry of calibration configuration ………………………………….. 44
Figure 3.2 Data processing algorithms ……………………………………………... 44
Figure 3.3 Geometry of transmission model for derivation of …………….. 46
Figure 3.4 Sampling arrangement of measured data for the SSP ……………. 47
Figure 3.5 Function at f = 90 MHz ……………………………………... 51
Figure 3.6 Estimated of the half-wave dipoles by MUSIC and the specific data processing works ………………………………………………………… 52
Figure 3.7 Estimated of the half-wave dipoles and the estimation errors by MUSIC(MOD) (simulation) ……………………………………………….. 56
Figure 3.8 Estimated of the LPDA by MUSIC(MOD) (measurement) ……….. 58
Figure 3.9 Estimated for the half-wave dipoles and the LPDA by MUSIC(MOD) ……………………………………………………………... 59
Figure 3.10 Estimated of the hybrid antenna by the MUSIC(MOD) (measurement) …………………………………………………………... 60
Figure 3.11 Estimated of the horn by MUSIC(MOD) (measurement) ………... 61
Figure 4.1(a) Three coupled inductors connected to a reference node …………….. 64
Figure 4.1(b) The equivalent circuit .………………………..…………………….... 64
Figure 4.2(a) Cancellation of the parasitic inductances of two capacitors by using three coupled inductors ………………………………………………….. 66
Figure 4.2 (b) the equivalent circuit ………………………………………………... 66
Figure 4.3 Symmetric configuration of parasitic inductance cancellation for three-capacitor EMI filter using three coupled inductors ……………….. 67
Figure 4.4 Equivalent half-circuits of Figure 4.3 …………………………………... 68
Figure 4.5 Diagram of design rule for determining parameters of three coupled inductors …………………………………………………………………. 70
Figure 4.6 Configuration of planar self-coupled winding ………………………….. 72
Figure 4.7 Insertion losses of compensated EMI filter for the DM and CM (simulation) ……………………………………………………………… 73
Figure 4.8 Test filter and two compensated circuits ………………………………... 74
Figure 4.9 Insertion losses of compensated EMI filter for the DM and CM (measurement) …………………………………………………………... 75
Figure 4.10 Insertion losses with parameter L1 variations. ………………………… 77
Figure 4.11 Insertion losses with parameter L2 variations …………………………. 78
Figure 4.12 Insertion losses with parameter L3 variations …………………………. 79
Figure 4.13 Insertion losses with parameter M12 variations ………………………... 80
Figure 4.14 Insertion losses with parameter M23 variations …………………………81
Figure 4.15 Insertion losses with parameter M13 variations ………………………... 82
Figure A.1 Circular ground plane with the V-shape edge-groove structure ………... 87
Figure A.2 Configuration of measurement …………………………………………. 88
Figure A.3 Elevations patterns with the V-shape edge-groove treatment ………….. 90
Figure A.4 Current density on the ground plane with V-shape edge-groove treatment ………………………………………………………………… 91
Figure A.5 Elevation patterns with different depth ……………………………… 91
Figure A.6 Elevation patterns with different width ……………………………. 92
Figure A.7 Elevation patterns with different diameters of ground planes (simulation) ……………………………………………………………… 94
Figure B.1 The equivalent circuit of transmit antenna ……………………………... 96
Figure B.2 The equivalent circuit of receive antenna ……………………………… 97
Figure B.3 The propagation model in horizontal polarization ……………………... 99
Figure B.4 The propagation model in vertical polarization ………………………. 100
Figure B.5 Configuration of NSA measurement ………………………………….. 105
Figure C.1 Three site attenuation measurements using three different antennas in pairs …………………………………………………….………………. 108


List of Tables
Table 2.1 The values of n and R for CBL6111C at h1 = 1 m, R = 3 m ……………... 29
Table 2.2 Comparison of geometries of NSA measurement between the tuned dipole and broadband antennas …………………………………………………. 36
Table 3.1 Measurement time required for the MUSIC(MOD) and other methods …… 62
Table 4.1 Parameters of complete and partial compensations ……………………… 71
Table B.1 Theoretical NSA of ideal site for tuned dipole antennas ………………. 104

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