Excitation shape and placement effects on natural radiating modes

Ghalib, Asim; Sharawi, Mohammad S.

doi:10.1109/apusncursinrsm.2017.8072125

Cited by 3 publications

(5 citation statements)

References 8 publications

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“…The presence of any antenna or deformation in the chassis greatly affect the chassis modes [43][44][45][46][47]. TCM was used in [48][49][50][51][52] to enhance the isolation between the MIMO antenna designs.…”

Section: Isolation Enhancement Using Tcmmentioning

confidence: 99%

Review of isolation enhancement with the help of theory of characteristic modes

Ahmad¹

2019

Eng. Appl. Sci. Lett.

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Multiple-input-multiple-output (MIMO) antennas performance can be degraded due to the poor isolation between the MIMO antenna elements. In this paper, we present a review of the different isolation enhancement schemes available in the literature. Empirically the isolation between the antennas can be improved by placing the antenna as far as possible and it can be enhanced further by introducing different isolation enhancement schemes. Theory of characteristic modes (TCM) was recently proposed that has useful benefits. TCM is also used to enhance the isolation. Moreover, this papers focus on the different approaches of TCM, to enhance the isolation.

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Section: Isolation Enhancement Using Tcmmentioning

confidence: 99%

Review of isolation enhancement with the help of theory of characteristic modes

Ahmad¹

2019

Eng. Appl. Sci. Lett.

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“…In many existing works, , a mobile terminal chassis was considered as the main radiating element for frequencies greater than 1 GHz when the chassis modes were excited. Remember that all these antennas have different applications such as MIMO, pattern reconfigurability, and wide‐band but the common thing is that all of them rely on the chassis as the main radiator.…”

Section: Introductionmentioning

confidence: 99%

New antenna mode generation based on theory of characteristic modes

Ghalib

Sharawi

2018

Int J RF Microw Comput Aided Eng

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In this article, the effect of actual antenna elements on rectangular chassis modes is investigated. The study is performed on three different antenna types, that is, printed inverted-F antenna (PIFA), printed monopole, and printed loop antennas. For the first time, we show that the presence of the antenna generates a completely new mode called the "antenna mode" (compared with chassis mode modifications as in other existing works). The new "antenna mode" only depends on the shape or geometry of the antenna and is independent of its location on the chassis (unlike chassis modes). In the presence of the antenna, the current maxima lies on the antenna element for all the modified chassis modes and the newly generated "antenna mode." In such scenarios, pure excitation of single characteristic mode (CM) is not possible with known existing techniques. K E Y W O R D S loop antenna, monopole, PIFA, TCM

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“…TCM was applied on the analysis of various different types of antennas such as wire antennas, handset antennas, printed MIMO antennas, and slot antennas . In Ref.…”

Section: Introductionmentioning

confidence: 99%

“…In Refs. , different slot shapes such as U, L, E, T, and circular were investigated. It was observed that as the size of the slot increases the modes get affected.…”

Section: Introductionmentioning

confidence: 99%

“…TCM was applied on the analysis of various different types of antennas such as wire antennas, 21 handset antennas, 22 printed MIMO antennas, [23][24][25] and slot antennas. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] In Ref. 43, it was shown that designs made with TCM are more robust under real-environment scenarios as compared to designs made with empirical methods.…”

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confidence: 99%

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Analysis of slot-based radiators using TCM and its application in MIMO antennas

Ghalib

Hussain

Sharawi

2018

Int J RF Microw Comput Aided Eng

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In this article, with the help of the theory of characteristic modes (TCM), it is found that the introduction of circular slots in a chassis modifies the chassis modes. Based on the location of the slot, different chassis modes will be affected. For a fixed location, the slot to chassis size ratio plays an important role in its effect on the radiating bandwidth (BW). For a small size ratio, a modified chassis mode will be created without affecting the radiating BW. The current concentration across the slot depends on the shape of the slot (circular, rectangular, triangular, or square) and its location on the chassis. Moreover, the effect of multiple circular slots on the chassis modes is investigated. For slots introduced in a symmetrical fashion, that is, four elements, the modes are not affected and are similar to the original chassis ones. We also investigate the principle behind frequency reconfigurability using TCM analysis. The varactors used for frequency reconfigurability do not alter the radiating BW (Modal Significance plots) but only help in the input impedance matching at different frequency bands of the same mode. If a mode is excited purely using a proper feeding arrangement, the same frequency reconfigurable antenna will behave as a wide band one. Based on the detailed analysis presented in this work, a compact multiple‐input‐multiple‐output annular slot frequency reconfigurable antenna operating between 1.8 and 2.45 GHz is presented. Frequency tuning is achieved using varactor diodes.

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Excitation shape and placement effects on natural radiating modes

Cited by 3 publications

References 8 publications

Review of isolation enhancement with the help of theory of characteristic modes

Review of isolation enhancement with the help of theory of characteristic modes

New antenna mode generation based on theory of characteristic modes

Analysis of slot-based radiators using TCM and its application in MIMO antennas

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