Book contents
- Frontmatter
- Contents
- Preface
- CHAPTER 1 INTRODUCTION
- CHAPTER 2 AN APPROXIMATE ANALYSIS OF THE CYLINDRICAL ANTENNA
- CHAPTER 3 THE TWO-ELEMENT ARRAY
- CHAPTER 4 THE CIRCULAR ARRAY
- CHAPTER 5 THE CIRCUIT AND RADIATING PROPERTIES OF CURTAIN ARRAYS
- CHAPTER 6 ARRAYS WITH UNEQUAL ELEMENTS; PARASITIC AND LOG-PERIODIC ANTENNAS
- CHAPTER 7 PLANAR AND THREE-DIMENSIONAL ARRAYS
- CHAPTER 8 TECHNIQUES AND THEORY OF MEASUREMENT
- Appendix I Tables of ΨdR, T(m) or T′(m) and self- and mutual admittances for single elements and circular arrays
- Appendix II Summary of the two-term theory for applications
- Appendix III Summary of formulas for the curtain array
- Appendix IV Tables of admittance and impedance for curtain arrays
- Appendix V Programme for Yagi-Uda array
- References
- List of symbols
- Index
CHAPTER 4 - THE CIRCULAR ARRAY
Published online by Cambridge University Press: 24 May 2010
- Frontmatter
- Contents
- Preface
- CHAPTER 1 INTRODUCTION
- CHAPTER 2 AN APPROXIMATE ANALYSIS OF THE CYLINDRICAL ANTENNA
- CHAPTER 3 THE TWO-ELEMENT ARRAY
- CHAPTER 4 THE CIRCULAR ARRAY
- CHAPTER 5 THE CIRCUIT AND RADIATING PROPERTIES OF CURTAIN ARRAYS
- CHAPTER 6 ARRAYS WITH UNEQUAL ELEMENTS; PARASITIC AND LOG-PERIODIC ANTENNAS
- CHAPTER 7 PLANAR AND THREE-DIMENSIONAL ARRAYS
- CHAPTER 8 TECHNIQUES AND THEORY OF MEASUREMENT
- Appendix I Tables of ΨdR, T(m) or T′(m) and self- and mutual admittances for single elements and circular arrays
- Appendix II Summary of the two-term theory for applications
- Appendix III Summary of formulas for the curtain array
- Appendix IV Tables of admittance and impedance for curtain arrays
- Appendix V Programme for Yagi-Uda array
- References
- List of symbols
- Index
Summary
The two-element array, which is investigated in the preceding chapter, may be regarded as the special case N = 2 of an array of N elements arranged either at the vertices of a regular polygon inscribed in a circle, or along a straight line to form a curtain. Owing to its greater geometrical symmetry, the circular array is advantageously treated next. Indeed, the basic assumptions which underlie the subsequent study of the curtain array (chapter 5) depend for their justification on the prior analysis of the circular array.
The real difficulty in analysing an array of N arbitrarily located elements is that the solution of N simultaneous integral equations for N unknown distributions of current is involved. Although the same set of equations applies to the circular array, they may be replaced by an equivalent set of N independent integral equations in the manner illustrated in chapter 3 for the two-element array. Since the N elements are geometrically indistinguishable, it is only necessary to make them electrically identical as well. One way is to drive them all with generators that maintain voltages that are equal in amplitude and in phase. When this is done all N currents must also be equal in amplitude and in phase at corresponding points. But this is only one of N possibilities. If the N voltages are all equal in magnitude but made to increase equally and progressively in phase from element 1 to element N, a condition may be achieved such that each element is in exactly the same environment as every other element.
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- Arrays of Cylindrical Dipoles , pp. 95 - 129Publisher: Cambridge University PressPrint publication year: 1968
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