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

This paper presents a design of a four-port, dual-band uniform circular array (UCA) to generate three orthogonal Orbital Angular Momentum (OAM) modes (OAM mode 0, +1 and -1) at two different frequency 2.45 GHz (ISM band/WLAN) and 5.4 GHz (WLAN). The proposed antenna is designed with the help of four 50-Ohm microstrip line radiator (MLR) having an annular slot on the ground plane. The effect of variation of the physical design parameters (like the length of 50-Ohm MLR, the radius of annular slot and annular slot width) on reflection coefficient and the radiation pattern is shown and discussed.

Dual-Band Triple Mode OAM Generation Using Annular Slot Microstrip Radiator

This paper proposes a hexagon patch antenna with six elliptical slots for V2V communication range as stated in IEEE 802.11p standard. The proposed geometry (Design I) is fabricated on FR-4 substrate and fed with the coaxial probe. The elliptical shape cuts are used to improve the directivity and gain. The measurement results are in good agreement with the simulation results. In Design II, the same circuit with defective ground structure has also been simulated, which further enhances the performance. The simulated results of design II show the gain of 6.021 dB and directivity of 9.443 dB in the band from 5.8 GHz to 6 GHz.

High Gain Hexagonal Patch Antenna for V2V Communication

In this paper, a new approach to design an antenna for low radar cross section (RCS) application using microstrip technology is developed. For this purpose, a rectangular patch antenna with rotated C-shaped slot for impedance matching, circular shaped slot in the center of the patch along with Complementary Split Ring Resonator (CSRR) is designed. To achieve a better reduction in the RCS at the desired central frequency, the radiating edges of the antenna are loaded with stepped impedance resonator, as levelled edges of the radiating surfaces contribute to an increased RCS. The antenna radiates at 2.3GHz, has an impedance bandwidth of 44.2MHz and a gain of 4.47dBi. The monostatic RCS is -24.77dBsm at the radiating frequency. Results show that loading the radiating edges with stepped impedance resonator and the addition of the planar metamaterials aid in the reduction of the RCS of the antenna.

Low RCS Antenna Loaded with Stepped Impedance Resonator and Metamaterials

This paper presents an unconventional design for a circular rat race coupler operating at 5 GHz frequency. The size of the novel design implemented is 21.68mm x 15.72mm. The unconventional design of the coupler allows 40% reduction in the size of the coupler as compared with the conventional rat race coupler without compromising on performance. Measured and simulated results of the S-parameters are provided.

Compact Horse Shoe Shape Rat-Race Coupler

Film Bulk Acoustic Resonator (FBAR) technology is one of the enabling technologies which fulfill the two major needs of wireless industry i.e. high operating frequency range and miniaturization of RF components. This paper presents the design and simulation of a FBAR with zinc oxide as the piezoelectric layer. In the present work, FBAR has been designed and simulated for piezoelectric thickness of 0.75 and 1.25 μm. A thickness of 0.75 μm corresponds to a simulated frequency of 3.57 GHz and can be used for WiMAX applications whereas a 1.25 μm thick layer is suitable for GSM applications at 1.94 GHz. The suitability of the structure for RF filter applications has been observed in terms of electromechanical coupling coefficient.

Madhur Deo Upadhayay

Papers

Dual-Band Triple Mode OAM Generation Using Annular Slot Microstrip Radiator

High Gain Hexagonal Patch Antenna for V2V Communication

Low RCS Antenna Loaded with Stepped Impedance Resonator and Metamaterials

Compact Horse Shoe Shape Rat-Race Coupler

Study on Design and Simulation of Zinc Oxide Based Film Bulk Acoustic Resonator for RF Filters