소형 안테나 ( Small Antennas )

Background and History. Resonator and Filter Topologies. Baw Device Basics. Design and Fabrication of BAW Devices. FBAR Resonators and Filters. Comparison with SAW Devices. Films Deposition for BAW Devices. Characterization of BAW Devices. Monolithic Integration. System-in-Package (SiP) Integration. Index.

RF bulk acoustic wave filters for communications

We report the first experimental generation of high-order Mathieu beams and confirm their propagation invariance over a limited range. In our experiment we use a computer-generated phase hologram. The peculiar behaviour of the vortices in Mathieu beams gives rise to questions about their orbital-angular-momentum content, which we calculate by performing a decomposition in terms of Bessel beams.

Holographic generation and orbital angular momentum of high-order Mathieu beams : Special issue on atoms and angular momentum of light

Recently, orbital angular momentum (OAM) based vorticose communication has attracted much attention because of its potential to significantly increase the spectrum efficiency (SE) of wireless communications. However, the multiple radio frequency (RF) chains used for multiple OAM modes lead to an unexpected cost for wireless vorticose communications. In this paper, we first propose the mode modulation (MM) based OAM system to allow multiple OAM modes sharing a common RF chain. The proposed MM cannot only reduce the hardware cost, but also boost the SE by introducing the mode as an additional dimension for data transmission. Moreover, without the channel state information (CSI) feedback, we develop an equal-probability mode modulation (EMM) scheme to maximize the SE of MM-based OAM systems with the limited RF chains. In addition, with the CSI feedback, we develop a Huffman coding based adaptive mode modulation (AMM) scheme, which can adaptively choose the OAM modes to further increase the SEs of OAM-based wireless communications. We also develop the joint power and probability allocation policy for the AMM scheme to achieve the maximum SEs for OAM-based vorticose communications. Numerical results demonstrate that the MM can offer a new mode dimension for vorticose communications and the AMM scheme can achieve larger SE than the EMM scheme.

Mode Modulation for Wireless Communications With a Twist

Electromagnetic (EM) waves with helical wavefront carry orbital angular momentum (OAM), which is associated with the azimuthal phase of the complex electric field. OAM is a new degree of freedom in EM waves and is promising for channel multiplexing in communication system. Although the OAM-carrying EM wave attracts more and more attention, the method of OAM generation at microwave frequencies still faces challenges, such as efficiency and simulation time. In this work, by using the circuit theory and equivalence principle, we build two simplified models, one for a single scatter and one for the whole metasurface to predict their EM responses. Both of the models significantly simplify the design procedure and reduce the simulation time. In this paper, we propose an ultrathin complementary metasurface that converts a left-handed (right-handed) circularly polarized plane wave without OAM to a right-handed (left-handed) circularly polarized wave with OAM of arbitrary orders and a high transmission efficiency can be achieved.

Ultrathin Complementary Metasurface for Orbital Angular Momentum Generation at Microwave Frequencies

Orbital angular momentum concept has discussed with the help of mathematical equations. An investigation of 8 elements uniform circular array (UCA) for different Orbital Angular Momentum (OAM) modes is carried out for three designs. The effect of array radius on OAM purity and the radial outward design to reduce phase complexity is discussed. Uniform circular antenna array for all possible combination has been simulated and its results are demonstrated for different physical and electrical characteristic.

Study of OAM mode purity by changing the orientation of antenna element

This paper presents a broadcasting antenna design operating at 2.4 GHz frequency. The proposed antenna is designed, simulated and fabricated on FR4 substrate of permittivity 4.1 and thickness 1.5 mm. The measured return loss is 17.5 dB at 2.4 GHz whereas the simulated return loss is 36.88 dB. Thus, the fabricated & simulated antenna are in good harmony. Also the cross polarization is less than −20 dB. This antenna can be used to broadcast on several type of wireless systems that we use in our day to day life like Amplitude modulation (AM), Frequency modulation (FM) radio, satellite telephony & Global Positioning System (GPS).

Slotted ground circular antenna for personal communication system (PCS) & broadcasting

This paper presents the generation of various OAM modes using novel spiral array of rectangular patch antennas. The proposed design ceases the requirement of a complex power dividing phased network. The presented OAM antenna is designed to resonate at 5.2 GHz for WLAN applications and can generate OAM beam with topology charge l = 0, ±1. A comparison study of the new OAM design with the conventional Uniform Circular Array (UCA) used for OAM modes generation is also presented.

A Spiral Array for OAM Mode Generation

This paper presents, design and simulation of a re-configurable ring resonator (RRR). The resonance frequency of the resonator can be re-configure by changing the biasing of diode. Change in resonant frequency is observed in diode on and diode off condition. This resonator can be re-configure from 3.17 GHz to 6.62 GHz in diode on and off condition. The proposed RRR can be used for low phase noise oscillator design.

Re-configurable ring resonator for oscillator application

This paper presents design of novel microstrip antenna for an 8-element linear array with 8x8 Butler Matrix as a beamforming network. The proposed structure resonates at 2.4 GHz frequency and is implemented using Microstrip Technology with FR-4 Substrate having er=4.3 and height=1.6 mm. Simulation results are given for the components (microstrip antenna, quadrature couplers, crossovers, phase shifters) used to implement the matrix. The 8-element antenna array is connected to the matrix to form a beamforming system and produces eight orthogonal beams at −55◦, −36◦, -21◦, -7◦, 55◦, 36◦, 21◦, and 7◦. The reflection coefficients and isolations at all ports are below −10 dB at the center frequency and side lobes of radiation pattern are sufficiently low. The applications for this technique are in lower frequency bands of 5G and LTE, wearable devices and IEEE 802.11 WLAN

/pdf/a-novel-antenna-for-8-element-beam-forming-antenna-array-9t15cnvnwg.pdf

Madhur Deo Upadhayay

Papers

Study of OAM mode purity by changing the orientation of antenna element

Slotted ground circular antenna for personal communication system (PCS) & broadcasting

A Spiral Array for OAM Mode Generation

Re-configurable ring resonator for oscillator application

A Novel Antenna for 8 Element Beam Forming Antenna Array using Butler Matrix