Microwave antennas—An intrinsic part of RF energy harvesting systems: A contingent study about its design methodologies and state‐of‐art technologies in current scenario

In this paper, Characteristics mode analysis (CMA) is introduced to study the dual-polarization behavior of simple monopole antenna. The antenna consists of monopole feed with symmetric arms (SA), resonating at 2.45 GHz and right-handed stub (RHS) is connected to resonate at 5.8 GHz. The SA has linear polarization and RHS has circular polarization. CMA is introduced to explore dual-polarized properties and validated on modal metrics. The intuition of antenna design is further extended to 4-port MIMO antenna configuration. Due to rotationally symmetrical connected ground topology, another induced resonance at 1.54 GHz is observed. A L-shaped stub is further connected to one-end of the monopole arm of each antenna element, that function as 2.5 GHz resonator and an effective isolator. The overall antenna dimension is 0.3 λ × 0.3 λ × 0.018 λ (where λ is the lowest operating wavelength) and the elements are spatially separated with edge-to-edge spacing of 0.018 λ with port isolations > 15 dB. The MIMO antenna operates at 1.54 GHz, 2.5 GHz with linear polarization and at 5.63 GHz as circular polarization. The antenna gains with radiation efficiencies are 0.62 dBi ( > 60%), 4 dBi ( > 70%) and 4.25–6 dBc ( > 80%). The computed ECCfar−fields is 0.3, showing its potential for pattern and polarization diversity MIMO environments. A prototype antenna is fabricated and measured with good agreements and found compatible for L-band, lower WLAN and upper WLAN applications.

CMA assisted 4-port compact MIMO antenna with dual-polarization characteristics

A chronological review of circularly polarized dielectric resonator antenna: Design and developments

Design and its state‐of‐the‐art of different shaped dielectric resonator antennas at millimeter‐wave frequency band

A compact single fed circularly polarized dielectric resonator antenna (CPDRA) for off-body communication in wireless body area network (WBAN) applications is proposed. The proposed antenna consists of a modified rectangular DRA made of Al2O3 with a permittivity of er = 9.8 and fed by a 50-Ω coaxial probe. Two unequal vertical slits are etched off from both the corner edges of the rectangular dielectric resonator to generate TE δ 11 x and TE 1 δ 1 y modes, and to reduce the overall size of the proposed antenna. Moreover, an efficient single layer equivalent phantom model is designed to reduce the simulation time for the analysis of off-WBAN communications. The proposed antenna is fabricated and characterized in free space as well as in on-body environment. It provides measured impedance and axial ratio (AR) bandwidths of 66.19% (4.72–9.39 GHz) and 15.01% (6.22–7.23 GHz) respectively in free space, 65.91% (4.73–9.38 GHz) and 16.02% (6.20–7.28 GHz) respectively in on-body environment. A full ground plane is used to provide unidirectional radiation pattern and greater isolation from the human body with low SAR i.e. 0.397 W/kg and 0.193 W/kg for 1 g and 10 g tissue respectively. These features make the proposed CPDRA is suitable for off-body communication and can easily be integrated in wireless devices.

Design and analysis of a compact circularly polarized DRA for off-body communications

This paper features, a comparative study of four different shaped dielectric resonator antennas (DRAs) for 60 GHz millimeter-wave applications. The proposed antennas are of different shapes i.e. cylindrical dielectric resonator antenna (CDRA), rectangular dielectric resonator antenna (RDRA), hexagonal dielectric resonator antenna (HDRA) and octagonal dielectric resonator antenna (ODRA) and each of the antenna is fed by a $50\ \boldsymbol{\Omega}$ microstrip line. These are placed on a silicon layer substrate ( $\boldsymbol{\epsilon}_{\mathbf{r}1}=4$ ), of 1.6 $(\mathbf{L}_{\mathbf{sub}1})\times 1.6(\mathbf{W}_{\mathbf{sub}1})\times 0.022(\mathbf{H}_{\mathbf{sub}1})\ \mathbf{mm}^{3}$ , followed by another silicon layer substrate ( $\boldsymbol{\epsilon}_{\mathbf{r}2}=11.9$ ), of 1.6 $(\mathbf{L}_{\mathbf{sub}2})\times 1.6(\mathbf{W}_{\mathbf{sub}2})\times 0.3(\mathbf{H}_{\mathbf{sub}2})$ mm3, This is placed on the bottom of DR. For the dielectric resonator (DR), high dielectric constant materials are used, Ca 5 Nb 2 TiO 12 ( $\boldsymbol{\epsilon}_{\mathbf{r}}=48$ ). Simulated S 11 for each of the antennas ≤ −10 dB, which covers an impedance bandwidth from 52.7- 62.8 GHz for CDRA, 57- 62.2 GHz for RDRA, 55.8- 64.6 GHz for HDRA and 54.2-63.5 GHz for ODRA. Other parameters such as gain, antenna efficiency, directivity and radiation pattern are obtained using the EM solver CST microwave studio and reported in this paper.

Priya Ranjan Meher

Papers

Microwave antennas—An intrinsic part of RF energy harvesting systems: A contingent study about its design methodologies and state‐of‐art technologies in current scenario

A chronological review of circularly polarized dielectric resonator antenna: Design and developments

Design and its state‐of‐the‐art of different shaped dielectric resonator antennas at millimeter‐wave frequency band

Design and analysis of a compact circularly polarized DRA for off-body communications

Design of Different Shaped DRAs for 60 GHz Millimeter-wave Applications