The Study of Periodic/non-period ic Ground Structure in Microstrip Circuit Yan Zhou Sho ol of Ele ctr onic I nformati on Eng ine eri ng Beijing University of Aeronautics & Astronautics Email: [email protected]Donglin Su Shoo l of Elec tron ic Inf orma tion Engin eer ing Beijing University of Aeronautics & Astronautics Email: [email protected]Abstract—The non-intact ground structure have been discussed in this paper. Using the unique transmit response of periodic PBG and non-periodic DGS structure, to weaken the effect of high rank harmonious wave and improve the frequent characteristic, and to realize effectual optimization and amelioration of passive circuit in microwave system especially at microstrip circuit .The simulation and test prove the validity and practicability of the periodic/non- periodic ground structure in microstrip circuit . I. I NTRODUCTION Periodic/non-periodic circuit ground structure have been researched deeply in recent years. Non-periodic defect ground system structure(DGS) and periodic photonic band gap structure(PBG) have been more and more used at modern transmit of light wave and microwave. DGS structure root in the application and extend of PBG in plane- microstrip circuit, a uique case of PBG. The concept of PBG come from the research for Photonic Crystal. Photonic crystal have characteristic of band gap at different direction and could weaken light wave at specifical frequency. At frequency of microwave and mm-wave , this phenomena have very much more applicatio n in recent ti me. We could get band stop transmit characteristic at 1-D, 2-Dor 3-D direction by using period PBG material or structure. DGS structure have similar effect but design is more agility. In plane microstrip circuit, period PBG and non-period DGS structure could be designed to realize wide-band filter. At field of antenna design, restraining surface wave and weakening cross interference is these structure’s unique advantage. In modern photon communication, PBG structure could improve the efficiency of LED, or reduce off band waste by way of frequency selection surface being incumbent on radiator. This paper based the fruit of PBG & DGS by previous people, fix the important on the transmission effect of period/non-period microstrip ground structure. And using HFSS to simulation a kind of UC-PBG band pass filter. This paper presents both basic characteristics and applications of period PBG and non-period DGS stricture. The characteristic of PBG and UC-PBG structure is introduced in Section II. The characteristic of DGS structure is introduced in Section III. And Section IV presents the the design method and the simulation by HFSS about UC-PBG band pass filter. All above followed by conclusions in Section V. II. THE CHARACTERISTIC OF PERIODIC PBG STRUCTURE IN MICROSTRIP CIRCUIT Photonic band gap (PBG) engineering has been observed widely in field of microwave and millimeter wave circuit. Applications of PBG materials or structure include microstrip filter, microstrip antennas, sesonant cavities, and so on. The still of plane PBG structure is very diversiform, such as fig.1, and could been realized in many ways, such as eroding some period units in medium layer, but these units does not penetrate ground. Another usual structure is UC-PBG (Unipalar Compact Photonic Bandgap), this PBG structure is realized with metal pads etched in the ground plane connected by narrow lines to form a distributed RLC network, such as fig. 2. Vias holes or multilayer substrates are not required in this novel PBG structure. A distinctive stopband over a wide range of frequency is observed and the measurement results agree with FEM simulation. This characteristic of UC-PBG could be used at filter design to optimize the frequency performance. Another unique feature of this PBG structure is the realization of a slow-wave microstrip line with low insertion loss. Slow-wave-mode propagation is of great interest for its use in reducing the dimension of distributed components in integrated circuits. The characteristic of PBG structure is defined by several elements such as the number of period units, the geometry structure of each period unit, the arrange still and dielectric coefficient, and so on. In antenna design, the PBG structure could weaken the surface wave loss radiating at dielectric layer and improve the efficiency of antenna and optimize its performance accordingly. And at the same time, this PBG/antenna structure could be seen a kind of slow-wave structure, In other application fields, the UC-PBG reflector put up a phenomena of PMC at the stopband frequency where the periodic loading changes the surface impedance to an open- circuit condition. The surface impedance of the proposed structure is frequency-sensitive since the PBG structure actually forms a distributed RLC network with specific resonant frequencies, such as fig.2. By way of most popular PBG circuit still, the UC-PBG structure could be formed easily with common eroding process. And UC-PBG could be integrated in MMIC, the compatibility of UC-PBG is better than other PBG plane still. The total microstrip with UC-PBG ground have better slow-wave effect
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8/13/2019 The Study of Periodic Non-periodic Ground