Microstrip and Printed Antenna Design
Written for practicing engineers new to the field, this book includes a succinct treatment of wireless designs with enough detail that CAD formulas may be implemented with relative ease.
TABLE OF CONTENTS Microstrip and Printed Antenna Design
2.5: ?/4 by ?/4 Wavelength Rectangular Microstrip Antenna
2.5 ?/4 by ?/4 Wavelength Rectangular Microstrip Antenna
Figure 2-13: ?/4 by ?/4 microstrip antenna.
When a = b the TM 01 and TM 10 modes have the same resonant frequency (square microstrip patch). If the patch is fed along the diagonal both modes can be excited with equal amplitude and in phase. This causes all four edges to become radiating edges. The two modes are orthogonal and therefore independent. Because they are in phase, the resultant of the electric field radiation from the patch is slant linear along the diagonal of the patch.
When a square microstrip patch is operating with identical TM 01 and TM 10 modes a pair of shorting planes exist centered between each of the pairs of radiating slots (Figure 2-14). We can replace the virtual shorting planes which divide the patch into four sections with physical shorting planes. We may remove one section and drive it separately due to the symmetry of the modes. This produces an antenna which is 1/4 the area of a normal rectangular patch antenna. [35]
Figure 2-14: Development of ?/4 by ?/4 microstrip antenna from a square microstrip antenna. When a square microstrip antenna is driven along the diagonal two virtual shorting planes appear. Replacing the virtual shorting planes with physical shorting planes allows one to remove a quarter section of the original antenna and drive it independently.
It is also possible to slightly make a ?
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