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Circularly polarized dual‐band zeroth order epsilon negative antenna using asymmetric unit cells
Author(s) -
Murugan Harish Adhithya,
Gudibandi Bharath Reddy,
Damodharan Sriram Kumar
Publication year - 2019
Publication title -
international journal of rf and microwave computer‐aided engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 39
eISSN - 1099-047X
pISSN - 1096-4290
DOI - 10.1002/mmce.21827
Subject(s) - physics , circular polarization , polarization (electrochemistry) , axial ratio , optics , resonator , chemistry , microstrip
In this paper, a dual‐band zeroth order resonance (ZOR) circularly polarized epsilon negative antenna is proposed for the case where shunt ZOR ( f sh ) is higher than series ZOR ( f se ). Epsilon negative unit cells resonate f sh , while a pseudo‐open termination unit cell with a series capacitance resonate f se , resulting in a dual‐band ZOR. The pseudo‐open termination unit cell can be placed anywhere around the epsilon negative unit cells for proper matching. Circular polarization (CP) is achieved by creating orthogonal components using asymmetric unit cells (AUCs). Zeroth order resonator inherently provides 90° phase shift between two orthogonal polarizations. Left hand circular polarization (LHCP) is achieved by adding stubs to the unit cells with two 90° right bends. Electric field distribution is used to verify the resonances for zeroth order and it is found that both the resonances follow zeroth order characteristics. The measured resonances are 4.11 GHz ( f se ) and 4.60 GHz ( f sh ) with measured average axial ratio of 2.4 dB at f se and 1.5 dB at f sh , respectively. The measured LHCP peak gain for f se is 1.53 dBic and for f sh is 2.34 dBic. The proposed design covers a frequency range of 3.6 to 4.6 GHz by varying the length of the stubs.