Impedance matrix representation for exponentially nonuniform transmission lines

✍ Scribed by L. Vegni; A. Toscano

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 109 KB
• Volume: 18
• Category: Article
• ISSN: 0895-2477
• DOI: 10.1002/(sici)1098-2760(199807)18:4<300::aid-mop15>3.0.co;2-7

✦ Synopsis

distance of the separation of the shorting post and the feeding probe. WHen using high-permittivity materials, the gain is very low, and the radiation pattern of the meandering patch antenna is not very good.

In this paper, a new kind of small microstrip antenna is proposed. From the study of an H slit on the microstrip patch, we find that the final resonant frequency is about 60% of the initial frequency. This means that cutting an H slit can minimize the antenna size from a half wavelength to a quarter wavelength. To demonstrate this idea, an H slit antenna which resonated at 910 MHz was fabricated. Its size was 60 mm = 70 mm compared to the usual size of 101 mm = 115 mm. From the comparison, we can see that cutting an H slit can effectively minimize the size of the antenna. Another advantage is its radiation pattern, as shown in Figure . The 3 dB beamwidth is 105Њ in the H-plane and 90Њ in the E-plane, and the cross polarization is less than 10 dB.

This method may be combined with other methods to obtain better features.

CONCLUSION

A multiport series inductance network model is established for the analysis of a slit cut on a microstrip patch antenna. Based on this analysis, two applications of the slit are proposed: to adjust the resonant frequency, and to make a small microstrip antenna. Experiments validate the model and the applications.