Fabrication of Tetra-band Filter on the Ceramic Substrate Reporter : Min-Tsang Yang Advisor : Chien-Min Cheng Hung-Chi Yang

Topics Introduction Design Flowchart Conclusion

Introduction Tetra-band bandpass filters could be used on GPS, WiMAX, and WLAN systems The characteristics of dielectric ceramic substrates are: r = 27.9 and Qf=33,100 In this research, three basic structures were adopted to accomplish the filter. triple-parallel-coupled2.45 and 5.2 GHz outer-frame structure1.57 GHz defected ground structure3.5 GHz.

The design flowchart Step 1 Use outer-frame structure to Generate 1.57 GHz Step 6 Use DGS (Defected Ground Structure) to modify 3.5 GHz Step 2 Use U-shaped resonator structure to generate 2.45 GHz and two zeros Step 3 Use triple-parallel-coupled microstrip line to generate 2.45 and 5.2 GHz Step 4 Combined Step 5 Tetra-band filters (1.57 / 2.45 / 3.5 / 5.2 GHz)

Outer-Frame Structure The function of this outer-frame are: Generate a 1.57 GHz filter Generate two zeros on upper stopband The first harmonic was fallen on 3.5 GHz

U-shaped resonators The function of this U-shaped resonator are: Generate a 2.45 GHz filter Two transmission zeros were generated beside the passband (2.45 GHz)

Modified triple-parallel-coupled line The function of this modified PCML are : Generate a dual-band bandpass filter (2.45/5.2 GHz) As the distance D increased , two zeros generated between two pass bands

Combination of Above Three Structures Combining the U-shaped resonators, Outer-frame structure and Triple-parallel-coupled microstrip line.

U-shaped DGS slot The function of this DGS are: As W increased gradually, the frequency shifted from 4 GHz to 3.5 GHz This DGS would enhance and modify the first harmonic of 1.57 GHz to an usable WiMax band

The final simulated result of tetra-band bandpass filter Frequency (GHz) Bandwidth (MHz / %) Insertion Loss (dB) 1.57 130 / 8.3 0.19 2.45 760 / 31 0.18 3.5 380 / 10.8 0.24 5.2 750 / 14.1 0.59

The merits of this structure were: Conclusion The merits of this structure were: The depth of zeros all over 30 dB. The stop-band rejection between 2.45 ~ 3.5 GHz was 20.6 dB, and 12.7 dB between 3.5 GHz ~ 5.2 GHz. The size of the filter was 26.310.5 mm2. All the other characteristics (bandwidth and insertion loss) of the four operating frequencies (1.57/2.45/3.5/5.2 GHz) were usable for the modern communication.

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