Manoj Stanley

The Limit of the Total Scattering Cross Section of Electrically Large Stirrers in a Reverberation Chamber

The total scattering cross section (TSCS) has been proven to be an effective quantity to characterize the performance of stirrers in a reverberation chamber (RC). It is shown in this letter that the maximum TSCS is a quarter of the stirring surface area, and it is equal to the absorption cross section (ACS) of the same area with perfect radio absorbers. The mathematical proof is presented and measurements are performed to validate this limit. It is also shown that the TSCS and ACS are statistical dual quantities; related dual quantities are also given. The TSCS can be used to characterize how well a stirrer is designed or how close an RC is to a perfect RC.

A Novel Reconfigurable Metal Rim Integrated Open Slot Antenna for Octa-Band Smartphone Applications

In this paper, a novel reconfigurable open slot antenna has been proposed for LTE smartphone applications to cover a wide bandwidth of 698–960 and 1710–2690 MHz. The antenna is located at the bottom portion of the mobile phone and is integrated with metal rim, thereby occupying a small space and providing mechanical stability to the mobile phone. Varactor diode is used to cover the lower band frequencies, so as to achieve a good frequency coverage and antenna miniaturization. The operational principles of the antenna are studied and the final design is optimized, fabricated, and tested. It has achieved the desired impedance bandwidth and the total efficiency of minimum 50% in free space throughout the required bands. The antenna performance with mobile phone components and human hand is also been studied. Furthermore, the SAR in a human head is investigated and is found to be within allowable SAR limits. Finally a multiple-input multiple-output antenna configuration with high isolation is proposed; it has an identical reconfigurable open slot antenna integrated at the top edge of the mobile phone acting as the secondary antenna for 698–960 and 1710–2690 MHz. Thus the proposed antenna is an excellent candidate for LTE smartphones and mobile devices.

B-Scan in a Reverberation Chamber

In this paper, the B-scan technique is applied to a reverberation chamber (RC) for the first time to characterize the time-domain behavior of the chamber. Based on B-scan measurement results, three things are studied in this paper. 1) The statistical behavior of the fields in the time domain is investigated, and it is found that the received power of the impulse response follows chi-square distribution with one degree of freedom. 2) The stirrer efficiency is quantified based on the equivalent total scattering cross section (TSCS) of stirrers, and this definition is not sensitive to the antenna position and load in the RC. It is shown that the stirrer efficiency defined in this paper provides, for the first time, a quantitative way to evaluate the stirrer design and the chamber performance. 3) A time-gating technique is proposed which provides an alternative method to eliminate the early time response and obtain the chamber transfer function of the RC accurately. This could be potentially used to increase the stirrer efficiency without changing the stirrers physically. It is demonstrated that the B-scan technique is a very useful approach for the study and evaluation of an RC.

3-D Antenna Radiation Pattern Reconstruction in a Reverberation Chamber Using Spherical Wave Decomposition

It has been shown that the correlation between the radiation patterns of two antennas can be measured in a reverberation chamber (RC). In this paper, it is shown that the self-correlation coefficient of an antenna, defined as the correlation between the radiation pattern of an antenna under test (AUT) and a transformed version of itself, can also be measured in an RC. It is found that the 3-D radiation pattern of the AUT can be reconstructed from the measured self-correlation coefficient by using spherical wave decomposition. Moreover, the axial ratio of the AUT can also be measured efficiently in the RC, when the pattern is directional. Numerical simulations and measurements in the RC and in an anechoic chamber have been undertaken. Good agreement is obtained, which confirms the validity of the proposed method. Thus, this novel method can become a very useful, cost-effective, and efficient method for 3-D antenna radiation pattern measurement.

A novel mm-Wave phased array antenna with 360° coverage for 5G smartphone applications

In this paper, a novel capacitive coupled patch antenna array capable of providing 360° coverage is proposed. The design and performance of the antenna element is discussed. The proposed antenna design is positioned in the mobile phone chassis as a set of 4 sub-arrays each with 12 antenna elements to provide high gain around 27 dBi with each sub-array providing 90° coverage. The antenna array covers the frequency range of 24–28 GHz which is a promising band for future 5G based smartphone services. The antenna array performance is evaluated. The proposed antenna exhibits a uniform radiation pattern with a stable gain when integrated with the mobile phone chassis.

Feasibility Study of Using the Housing Cases of Implantable Devices as Antennas

A novel antenna design for implantable pacemakers is proposed. The housing of a pacemaker is utilized as an antenna to cover both the 402-405 MHz Medical Implant Communication Service band and the 433-MHz Industrial, Scientific and Medical band. This is achieved by exploiting radiating characteristic current modes of the housing case. These modes are excited using a capacitive coupling element with the help of a matching circuit. The radiation pattern of this antenna is optimized to be in a desirable direction away from the body (off-body direction). The ability of the proposed antenna for communications is demonstrated using a transceiver and a base station at 433 MHz. A communication range of 1 m is established when a transmitter with the proposed antenna is implanted in a rabbit and the power fed by the transceiver to the antenna is 25 μW. A longer range of up to 19 m can be established with the maximum allowable transmit power within the safety limits. Furthermore, the far field wireless power transfer through the proposed antenna is investigated by experiment. A received power of up to 22.38 μW by the proposed antenna is demonstrated when an equivalent isotropically radiated power of 140 mW is transmitted 1 m away from a transmitting antenna. From the same transmitting antenna in the same distance, a power of 4 mW can be received when the transmit power is within safety limits. This power can be used to recharge a small battery or a capacitor, which can potentially cover the communication power consumption of the pacemaker and hence extend the life span of the primary battery.