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3. MEASUREMENT AND DISCUSSION

The measured return loss, radiation efficiency, peak gain,  XY -cut 2D pattern, XZ -cut 2D patternand Y Z -cut 2D pattern of on-board GSM PIFA with/without copper strip are shown in Figs. 3–8,respectively. From those measured results, it can be observed that the GSM PIFA with/withoutcopper strip performs almost the same return loss (S 11) but different radiation efficiency, peak gainand radiation pattern. Furthermore, the TRP/TIS showing in Fig. 9 and Fig. 10 reveal that theGSM PIFA with copper strip has much more compromised active results (TRP     27dBm andTIS     100 dBm for E-GSM 900, TRP    24 dBm and TIS     100 dBm for DCS 1800) than thatwithout copper strip, especially for TIS [9]. This is because the copper strip serves as a reflector formodifying the radiation pattern of GSM PIFA while the distant between copper strip and antennais properly decided (∼ λ/8). Then the radiation pattern is concentrated in front of the reflector,isolating the EMI noise from PCB and eliminating EM wave power reflected by complex PCBenvironment behind the reflector. This is the reason why the TIS can be substantially improved inE-GSM 900 band. Furthermore, TRP is generally enhanced during the frequency band of E-GSM900 and DCS 1800.

Name W W1 W2 W3 W4 W5 W6 L L1 L2 L3 L4 H

Size 60 57 7 9 21 18 6 140  100  8 5 14 1.6 

Unit mm mm mm mm mm mm mm mm mm mm mm mm mm

Figure 2: The dimension of on-board GSM PIFA.

Frequency(MHz)

800 1000 1200 1400 1600 1800 2000

       S      1      1       (       d       B       )

-25

-20

-15

-10

-5

0

Antenna w/o reflector

Antenna w/i reflector

Figure 3: Measurement of  S -parameter.

Frequency(MHz)

800 1000 1200 1400 1600 1800 2000

      E       f       f      i     c      i     e     n     c     y

0.0

0.2

0.4

0.6

0.8

1.0

Antenna w/o reflector

Antenna w/i reflector

Figure 4: Measurement of radiation efficiency.

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Peak Gain

Frequency(MHz)

800 1000 1200 1400 1600 1800 2000

       d       B       i

-16

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

Antenna w/o reflector

Antenna w/i reflector

Figure 5: Measurement of peak gain.

XY-Cut 2D Pattern E-totel

-35 -30 - 25 -20 -15 -10 -5 0 5

-35

-30

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5

-35-30-25-20-15-10-505

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5

0

30

60

90

120

150

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210

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270

300

330

900MHz(Antenna w/o reflector)

1800MHz(Antenna w/o reflector)

900MHz(Antenna w/i reflector)

1800MHz(Antenna w/i reflector)

Figure 6: Measurement of  XY -cut 2D pattern.

XZ-Cut 2D Pattern E-totel

-35 -30 -25 -20 -15 -10 -5 0 5

-35

-30

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5

-35-30-25-20-15-10-505

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5

0

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120

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240

270

300

330

900MHz(Antenna w/o reflector)

1800MHz(Antenna w/o reflector)

900MHz(Antenna w/i reflector)

1800MHz(Antenna w/i reflector)

Figure 7: Measurement of  XZ -cut 2D pattern.

YZ-Cut 2D Pattern E-totel

-35 -30 -25 -20 -15 -10 -5 0 5

-35

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-35-30-25-20-15-10-505

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900MHz(Antenna w/o reflector)

1800MHz(Antenna w/o reflector)

900MHz(Antenna w/i reflector)

1800MHz(Antenna w/i reflector)

Figure 8: Measurement of  Y Z -cut 2D pattern.

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20

21

22

23

24

25

26

27

28

29

30

880 897.4 914.8 1710.2 1747.4 1784.8

      d      B     m

Frequency(MHz)

Antenna w/o reflector

Antenna w/i reflector

Figure 9: Measurement of TRP of antenna.

95

96

97

98

99

100

101

102

103

104

105

925.2 94 2.4 959.8 1 805.2 1842 .4 1 879.8

      d      B    m

Frequency(MHz)

Antenna w/o reflector

Antenna w/i reflector

Figure 10: Measurement of TIS of antenna.

4. CONCLUSION

The comprehensive measurement and comparison of on-board GSM PIFA with and without copperstrip are presented. The passive measured results of GSM PIFA present that the radiation effi-ciency and peak gain can be obviously enhanced while the copper strip, i.e., reflector, is attached.Furthermore, the active measurement also verifies that the communication quality of this GSM-based wireless home system product is effectively improved while the reflector is attached. Thoseexperiments reveal that the reflector made by a simple copper strip make great improvement inGSM wireless communication quality due to the isolation of EMI noise from PCB and modificationof antenna pattern.

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5. Hung, W.-L., “Design and study of small PIFA structures,” 18–32, Jun. 2007.6. Chang, Y.-H., “Design of compact printed dual-band and ultra-wideband monopole antenna,”

26–33, Jul. 2008.7. Lai, K.-C., “Design and measurement of ultra wide band antenna,” 21–37, Jul. 2008.8. Chen, W.-S., “Studies of dual-band and broadband printed slot antennas,” 57–69, Jan. 2001.9. Alpaslan, A., “Global test specification for terminals for performance measurements — Per-

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