A signal- and noise-measurement procedure for an antenna/RF receiver combination in a short-range automotive communication system
✍ Scribed by Victor Rabinovich; Basim Al-Khateeb; Barbara Oakley; Nikolai Alexandrov
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 152 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0895-2477
No coin nor oath required. For personal study only.
✦ Synopsis
ing-frequency bands was constructed. In this case, ⌬l is set to be 0 mm, and the dimensions of s and d are selected to be 4 and 19.5 mm, respectively. The measured and simulated (by IE3D) return losses against frequency for antenna A are shown in Figure 2. Agreement between them is satisfactory, except for the slight frequency deviations that can mainly be due to the error of the substrate permittivity. From the experimental results, it is observed that 10-dB input-impedance bandwidths centered at 2090 and 5505 MHz are 1.9% and 9.8%, respectively, for the two operating frequency bands, which are due to the square-ring and rectangular microstrip antennas. The radiation patterns measured at 2090 and 5505 MHz are also plotted in Figures 3 and4, respectively. The broadside radiation patterns are seen at the two operating frequencies. The peak gain is about 4.2 dBi for the square-ring microstrip antenna and 7.5 dBi for the rectangular microstrip antenna.
The prototype (antenna B) of the proposed dual-frequency microstrip antenna with dual polarization (CP/LP) radiations was also implemented. The dimensions of the square-ring and rectangular patches are the same as those of antenna A, except that ⌬l ϭ 4.6 mm. To achieve the impedance matching of the CP square-ring microstrip antenna, the dimensions of s and d are changed to 2 and 15 mm, respectively. Figure 5 presents the experimental results of Antenna B, together with the simulated results. The measured 10-dB input-impedance bandwidth is about 2.4% (with reference to the center frequency of 2094 MHz) for the CP square-ring microstrip antenna and 7.5% (referred to the center frequency 4980 MHz) for the LP rectangular microstrip antenna. It has to be noted that the center frequency of the rectangular microstrip antenna is decreased from 5505 (antenna A) to 4980 MHz (antenna B) is due to the changes of the feed position, which is necessary to achieve the impedance matching for the CP square-ring microstrip antenna. The axial ratio in the lower frequency band of antenna B is also measured and presented in Figure 6. The 3-dB axial-ratio CP bandwidth is about 0.7%. The radiation patterns at 4980 MHz for antenna B is similar to the results shown in Figure 4.
4. CONCLUSION
The dual-frequency microstrip antenna that can produce the identical linear polarization or dual polarizations at two operatingfrequency bands has been proposed and the antenna prototypes are constructed and tested. The two resonant frequencies of the dualfrequency antenna are due to a square-ring microstrip antenna and a rectangular microstrip antenna, respectively. Hence, the broadside radiation patterns can be obtained in the two operating-frequency bands. The measured results have good agreements with the simulated results, which provide the experimental validation.