| With the proposal and development of fifth generation of mobile communication（5G）,higher requirements for the design of filter at microwave mm-wave frequency-band is addressed.However,the appearance and development of Intertgrated Subatrate Gap Waveguide（ISGW）has provided new thoughts and new paths to design of such filters,because ISGW has not only advantages that Substrate Integrated Waveguide（SIW）has in applying dielectric Substrate processing to such a design,but also its gap height more stable and processing cost lower than that of Gap Waveguide（GW）,as well as capable of surface wave suppression and loss reduction resulting from space radiation due to transmission lines,the characteristic of self-encapsulation to meet requirements for development of microwave mm-wave circuit system,and can be processed with PCB board thus a good integration simultaneously.Its good characteristics of device design and advanced systematic integration can be expected for playing an important role in device design at microwave mm-wave frequency-band in the development of fifth generation of mobile communications.Main studies in the paper are as below:（1）A 5G mm-wave bandpass filter based on improved TOLR of ISGW was proposed: by using the characteristic of super magnetic permeability of TOLR under mm-wave frequency-band to design the filter circuit and as the result,its improved TOLR made such a filter designed more compact and further miniaturized,together with three layers of ISGW structure,the integrated design of the mm-wave bandpass filter was completed.The central frequency of the filter was 27 GHz,the frequency range of 3d B band width was from 24 GHz to 30 GHz with relative band width as 22.2%,which perfectly covered the first frequency-band of 5G mm-wave spectrum published by our State,and because of 0° degree feed structure applied to the filter design,as a result,after the transmission zero was introduced respectively at each frequency point22.3GHz and 32.9GHz,the performance of out-of-band suppression of the filter was improved.It was clear from the table of Chapter III of performance comparison with that from other literature,that advantages of this filter design based on ISGW structure over that by other technologies are: the insertion loss of this design is less than 0.3d B,and the return loss is more than 10 d B,performances of loss mentioned are relative lower than the high frequency filter designed by other technologies.Detailed theoretical analysis and interpretations were paid to the working principle and design concept of the filter,and the design flow of mm-wave bandpass filter was summarized.（2）A tunable 5G mm-wave bandpass filter based on ISGW zero pole was proposed:through construction of zero pole of filter resonator pair to design a bandpass filter with two transmission pole and four transmission zero at 20.5GHz,24 GHz,29.6GHz and31.1GHz,each of its transmission zero was tunable individually,its central frequency was 26.62 GHz,frequency range of 3 d B band width was from 25.56 GHz to 27.68 GHz,insertion loss was less than 0.8d B and return loss more than 25 d B.In comparison,its performances of simulation and testing after processing nearly matched,and its processes was suitable for industrialized mass production.In the end,the method of the filter above was interpreted in detail and proved effective and convenient,and its design flow based on ISGW resonator pair zero pole construction was summarized. |
