Characteristic modes of circular slot antennas etched on a finite ground plane

Self Cite

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.

“…Whenever a slot is introduced in the chassis, previous works in Refs. mentioned that new slot modes are created. Are these actual slot modes?…”

Section: Slot Effect On Chassis Modesmentioning

confidence: 99%

“…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%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Ghalib

Hussain

Sharawi

2018

Self Cite

“…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

Self Cite

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

A compact multi‐band multi‐input multi‐output antenna for 4G/5G and IoT devices using theory of characteristic modes

Kumar

Khanna

2019

A compact four element multi-band multi-input multi-output (MIMO) antenna system for 4G/5G and IoT applications is presented in this paper. The proposed antenna is developed using the theory of characteristic modes helping in systematic design of MIMO antenna system. It consists of four L-shaped planar inverted-F antenna (PIFA) elements each operating at 3.5, 12.5, and 17 GHz bands with the bandwidth of 359 MHz, 1 GHz, and more than 3.7 GHz, respectively. The proposed antenna system is suitable for both 4G/5G and internet of things devices as it shows the satisfactory MIMO system performance. Good isolation characteristics are observed by implementing complimentary Metamaterial structure on the ground plane resulting in isolation level lower than −21 dB between the antenna elements. The proposed antenna is fabricated and experimental results are also presented and discussed. K E Y W O R D S5G, IoT, multi-input multi-output, planar inverted-F antenna, theory of characteristic modes