### Cell Phone Signal Testing with Infra

- Red Reflective Windshield

A test was conducted at an independent antenna range using Infra

- Red (IR) Reflecting windshield on a family sedan (Toyota Camry) and the results compared to the same testing with a standard windshield. The testing included signal strength measur ements at different locations of the cell phone: Driver Right, Rear Passenger Outer, Rear Passenger Inner. The testing was then repeated with several deletion patterns, all of which comply with the CARB regulations as written in the 15

- day notice published on December 15, 2009.
The results of the signal testing showed very little variation between standard windshield and IR Reflective windshield. The data shows that the signal strength is almost the same for the cell phone user in the front of the vehicle, but is actually stronger in the rear of the vehicle when an IR Reflective windshield is present. Therefore, a passenger in the back seat would actually have a higher probability of completing a call when an IR Reflective windshield is installed, whereas th e driver would see no difference.

Test Results:
The testing for a cell phone located at the driver’s right side, towards the middle of the vehicle, shows that for this worst case scenario, the signal strength is almost identical regardless of what kind of windshield is present. Various deletion patterns were tested to determine how specific deletion patterns would influence signal strength. The results show that the deletion may not even be necessary for cell phone signals. The variations due to coated gla ss are well within the normal cell signal variation.
The results show that a cell phone in the rear seat location would actually have a better chance at getting a call completed when an IR Reflective windshield is installed. There is some variation, based on deletion patterns, in the signal strength when the cell phone is in the middle of the rear seat location. However, when the cell phone is towards the outside of the vehicle in the rear seat, almost all combinations of IR Reflective windshield result in a stronger cell phone signal than with a conventional windshield. The results are presented here in detail. Pittsburgh Glass Works, LLC 30 Isabella Street Pittsburgh, PA 15212 Telephone (412) 995

- 6482 mrustagi@pgwglass.com www.pgwglass.com

Mukesh Rustagi Director, Strategic Product Management

### Driver Cell Phone Signal :

The first figure shows standard glass compared to IR Reflective glass with no deletions, and two different deletion patt erns.

The second figure shows additional deletion patterns compared to standard glass. In all cases, the signal is actually only marginally different from one frequency to next and well within the normal variations of the various signal frequencies.

With various deletion patterns, the average signal loss can be as small as 0.2 dB, which is considered insignificant and well within the margin of error. Therefore, a cell phone held at the driver’s right would have the same signal in a vehicle equipped w ith IR Reflecting windshield as one with standard windshield. -20.0 -15.0 -10.0 -5.0 0.0 5.0

824 829 834 839 844 849 868.5 874 879.3 883.6 889.4 894 1850 1860 1870 1880 1890 1900 1910 1920 1929.6 1938.4 1950 1960 1970.4 1980 1990 Average Gain (dBi)



## Frequency (MHz) Driver Right Cellular Average Gain

- Deletion Patterns

Regular W/S l(Avg Gain -1.7 dBi) No Deletion (Avg Gain -2.5dBi) Deletion A (Avg Gain -2.2) Deletion B (Avg Gain -2.2dBi)

-20.0 -15.0 -10.0 -5.0 0.0 5.0

824 829 834 839 844 849 868.5 874 879.3 883.6 889.4 894 1850 1860 1870 1880 1890 1900 1910 1920 1929.6 1938.4 1950 1960 1970.4 1980 1990 Average Gain (dBi)

Frequency (MHz) Driver Right Cellular Average Gain

- Additional Deletion Patterns

Regular W/S l(Avg Gain -1.7 dBi) Deletion C (Avg Gain -2.0dBi) Deletion D (Avg Gain -1.9) Deletion E (Avg Gain -2.2) Deletion F (Avg Gain -2.0dBi)

### Rear Passenger Inner Cell Phone Signal:

The test results of cell phone signal in the rear center of the vehicle shows an actual improvement of signal strength , with some deletion patterns, when an IR Reflective windshield is present.

The next figure demonstrates that other deletion patters are available that can improve the average signal by as much as 0.3 dB for a cell phone located in the rear seat middle.

The variation in signal strength in the rear seat demonstrates once again that the signal variation is minimal between a vehicle equipped with an IR Reflective windshield and one with a standard windshield. The variation in average signal strength is within the margin of error. -20.0 -15.0 -10.0 -5.0 0.0 5.0

824 829 834 839 844 849 868.5 874 879.3 883.6 889.4 894 1850 1860 1870 1880 1890 1900 1910 1920 1929.6 1938.4 1950 1960 1970.4 1980 1990 Average Gain (dBi)



## Frequency (MHz) Rear Passenger Inside Cellular Average Gain

- Deletion Patterns

Regular W/S l(Avg Gain -4.2 dBi) No Deletion (Avg Gain -4.7dBi) Deletion X (Avg Gain -4.5) Deletion A (Avg Gain -4.4) Deletion B (Avg Gain -4.0dBi)



### -20.0 -15.0 -10.0 -5.0 0.0 5.0

824 829 834 839 844 849 868.5 874 879.3 883.6 889.4 894 1850 1860 1870 1880 1890 1900 1910 1920 1929.6 1938.4 1950 1960 1970.4 1980 1990 Average Gain (dBi)



## Frequency (MHz) Rear Passenger Inside Cellular Average Gain

- Additonal Deletion Patterns

Regular W/S l(Avg Gain -4.2 dBi) Deletion C (Avg Gain -4.2dBi) Deletion D (Avg Gain -4.6) Deletion E (Avg Gain -3.9dBi)

### Rear Pa ssenger Outer Cell Phone Signal:

The test results of cell phone signal in the rear seat nearer to the windows of the vehicle shows an actual impro vement of signal strength, without any deletions , when an IR Reflective windshield is present.

Additonal d eletion patterns reconfirm that the signal is actually stronger, by as much as 0.5 dB with one particular pattern.

Therefore, a passenger in the rear seat is more likely to be able to complete a cell phone call if there is an IR Reflective windshield t han otherwise. Even though this variation is relatively small, the data shows that the IR Reflective windshield is consistently better for cell phone signals in the 850 MHz band used by AMPS cell phones. For the PCS cell phones, there is no difference in t he cell phone reception whether an IR windshield is used or not. -20.0 -15.0 -10.0 -5.0 0.0 5.0

824 829 834 839 844 849 868.5 874 879.3 883.6 889.4 894 1850 1860 1870 1880 1890 1900 1910 1920 1929.6 1938.4 1950 1960 1970.4 1980 1990 Average Gain (dBi)



## Frequency (MHz) Rear Passenger Outer Cellular Average Gain

- Deletion Patterns

Regular W/S l(Avg Gain -1.9 dBi) No Deletion (Avg Gain -1.7dBi) Deletion X (Avg Gain -2.1) Deletion A (Avg Gain -1.8) Deletion B (Avg Gain -2.0dBi)

-20.0 -15.0 -10.0 -5.0 0.0 5.0

824 829 834 839 844 849 868.5 874 879.3 883.6 889.4 894 1850 1860 1870 1880 1890 1900 1910 1920 1929.6 1938.4 1950 1960 1970.4 1980 1990 Average Gain (dBi)



## Frequency (MHz) Rear Passenger Outer Cellular Average Gain

- Additional Deletion Patterns

Regular W/S l(Avg Gain -1.9 dBi) Deletion C (Avg Gain -1.7dBi) Deletion D (Avg Gain -1.4) Deletion E (Avg Gain -1.8 dBi)

### Conclusion

When considering the actual cell phone reception in a vehicle, it is important to look at the actual signal strength when drawing conclusions. The vehicle is a very dynamic environment and its location and orientation changes with respect to a cell tower. If the signal is really weak, a vehicle equipped with an IR Reflective windshield may actually be better for a cell phone call in certain situations, whereas a vehicle equi pped with standard windshields may be better at other times. On average, the data shows that there is no significant difference in cell phone reception between a vehicle equipped with IR Reflective windshield and one with standard windshield.