# US 2021/0242606 A1 · Extremely electrically small antennas based on multiferroic materials > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242606 A1 - Document ID: US20210242606A1 - Status: Published application - Kind: A1 - Application number: 17/168,048 - Filed: 2021-02-04 - Published: 2021-08-05 - Earliest claimed: 2018-08-09 - Assignees: The Regents of the University of California - Applicants: The Regents of the University of California - Inventors: Abdon E. Sepulveda; Gregory P. Carman; Jinzhao Hu; Joseph Devin Schneider; Elmer Wu; Zhi Yao; Sidhant Tiwari; Wenzhong Yan - Web page: https://patentgrep.com/patent/US20210242606A1 ## CPC - H01Q 9/0407: {Substantially flat resonant element parallel to ground plane, e.g. patch antenna (dipole H01Q9/285; monopole H01Q9/40)} - H01Q 21/067: {using endfire radiating aerial units transverse to the plane of the array} - H01Q 1/38: formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142)} - H01Q 3/44: varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element - H03H 9/02228: {Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer} - H03H 9/175: {Acoustic mirrors} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A multiferroic antenna apparatus and method are described which provides increased energy efficiencies and ease of implementation. Magnetoelastic and/or magnetostrictive resonator are coupled to a piezoelectric substrate, along with electrodes coupled to its opposing surfaces. In receive mode the resonators create mechanical waves in response to being excited into magnetic oscillation by receiving electromagnetic radiation, and these mechanical waves coupled to the piezoelectric substrate causing it to generate an electrical output signal at said electrodes. In transmit mode an electrical signal coupled through the electrodes induces mechanical waves in the piezoelectric substrate directed to the resonators which are excited into magnetic oscillation to output electromagnetic waves. ## Claims ### Claim 1 A multiferroic radio frequency antenna apparatus, comprising: a piezoelectric substrate; at least one pair of electrodes coupled to said piezoelectric substrate; and a plurality of magnetoelastic and/or magnetostrictive resonators coupled to said piezoelectric substrate; wherein said electrodes in combination with piezoelectric substrate convert between radio frequency electrical signals input at the electrodes to mechanical waves in the piezoelectric substrate, or from mechanical waves in the piezoelectric substrate to radio frequency electrical signal from the electrodes; wherein said magnetoelastic and/or magnetostrictive resonators in combination with said piezoelectric substrate convert between radio frequency electromagnetic waves input at said magnetoelastic and/or magnetostrictive resonators to mechanical waves in said piezoelectric substrate, or from mechanical waves in said piezoelectric substrate to radio frequency electromagnetic waves from said magnetoelastic and/or magnetostrictive resonators; and wherein said antenna apparatus performs reception in response to converting radio frequency electromagnetic radiation into radio frequency electrical signals, and performs transmission in response to converting radio frequency electrical signals into radio frequency electromagnetic radiation. ### Claim 2 A multiferroic radio frequency antenna apparatus, comprising: a piezoelectric substrate; at least one pair of electrodes, coupled to said piezoelectric substrate, and configured for converting between an electrical signal at the electrodes to mechanical waves in the piezoelectric substrate, or from mechanical waves in the piezoelectric substrate to electrical signals at the electrodes; and a plurality of magnetoelastic and/or magnetostrictive resonators, coupled to said piezoelectric substrate, and configured for converting between mechanical waves in the piezoelectric substrate to electromagnetic waves from the magnetoelastic and/or magnetostrictive resonators, or from electromagnetic waves received by the magnetoelastic and/or magnetostrictive resonators into mechanical waves in the piezoelectric substrate; wherein said piezoelectric substrate interfaces between said at least one pair electrodes and said plurality of magnetoelastic and/or magnetostrictive resonators to transmit electromagnetic signals by converting radio frequency electrical signals applied at said electrodes into electromagnetic waves from the magnetoelastic and/or magnetostrictive resonators, and to receive electromagnetic signals by converting electromagnetic waves received at said magnetoelastic and/or magnetostrictive into radio frequency electrical signals at said electrodes. ### Claim 3 A multiferroic radio frequency antenna apparatus, comprising: a piezoelectric substrate; a plurality of magnetoelastic and/or magnetostrictive resonators coupled to said piezoelectric substrate; at least one pair of electrodes, having a first electrode coupled to a first surface plane of said piezoelectric substrate, and a second electrode coupled to a second surface plane of said piezoelectric substrate; wherein in receive mode said plurality of magnetoelastic and/or magnetostrictive resonators create mechanical waves in response to being excited into magnetic oscillation by receiving electromagnetic radiation, and these mechanical waves coupled to the piezoelectric substrate cause it to generate an electrical output signal at said electrodes; and wherein in transmit mode an electrical signal coupled through said electrodes to the piezoelectric substrate induces mechanical waves directed to said plurality of magnetoelastic and/or magnetostrictive resonators which are excited into magnetic oscillation to output electromagnetic waves. ### Claim 4 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said antenna apparatus is configured for transmitting or receiving radio frequency electromagnetic radiation. ### Claim 5 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein dynamic magnetic flux current oscillations in said plurality of magnetoelastic and/or magnetostrictive resonators are used as a fundamental source for detecting or radiating radio frequency electromagnetic waves. ### Claim 6 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein wavelengths of the mechanical waves in said piezoelectric substrate are orders of magnitude smaller than wavelengths of the radio frequency electromagnetic waves which are received or transmitted from said magnetoelastic and/or magnetostrictive resonators, allowing said antenna apparatus to be orders of magnitude smaller than a conventional electromagnetic antenna operating at an identical radio frequency. ### Claim 7 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said electrodes comprise a first electrode coupled to a first surface plane of said piezoelectric substrate, and a second electrode coupled to a second surface plane of said piezoelectric substrate. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein said first electrode or said second electrode is configured in a pattern with open spaces within each of which are disposed an array of magnetoelastic and/or magnetostrictive resonators. ### Claim 9 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said piezoelectric substrate uses dynamic strain in converting between electrical signals and mechanical waves. ### Claim 10 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said mechanical waves comprise a shear wave. ### Claim 11 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said plurality of magnetoelastic and/or magnetostrictive resonators are configured to transfer between electromagnetic waves and mechanical waves in response to their natural frequency. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein size, shape, and distance relationships between said plurality of magnetoelastic and/or magnetostrictive resonators and said electrodes determine the resonant parameters. ### Claim 13 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said electrodes comprise a detector for measuring voltage and generating an output to a grounded coplanar waveguide. ### Claim 14 (depends on 1, 2, 3) The apparatus of any of claims 1-3, wherein said mechanical waves comprise a shear wave, or a shear-horizontal wave, or a lamb wave, or any combination of shear wave, shear horizontal wave and lamb wave. ### Claim 15 (depends on 1, 2, 3) The apparatus of any of claims 1-3, further comprising incorporating islands of floating magnetoelastic (ME) material between at least one pair of electrodes. ### Claim 16 (depends on 1, 2, 3) The apparatus of any of claims 1-3, further comprising an antenna switching circuit configured for switching m radio-frequency sources or inputs, between n different multiferroic antennas in response to receiving at least one control voltage in a time varying antenna, wherein value n is larger than m. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein at least a portion of said n different multiferroic antennas operate at different frequency ranges, toward broadening frequency range of said multiferroic radio frequency antenna apparatus to reach broad band radiation. ### Claim 18 A method of generating electromagnetic radiation at radio frequencies into free space, comprising: utilizing magnetoelastic and/or magnetostrictive material as resonators to create or receive mechanical waves across a piezoelectric substrate to electrodes upon which an electrical signal is created or received. ### Claim 19 (depends on 18) The method of claim 18, further comprising incorporating mechanical acoustic energy reflecting mechanisms toward enhancing mechanical wave strength and/or electrical signal strength. ### Claim 20 (depends on 19) The method of claim 19, wherein said mechanical acoustic energy reflecting mechanisms are selected from the group of mechanical acoustic energy reflecting mechanisms consisting of Bragg acoustic mirrors, acoustic gratings, trenches, and air cavities, toward enhancing mechanical wave strength and/or electrical signal strength. ### Claim 21 (depends on 18) The method of claim 18, wherein said mechanical waves comprise a shear wave, or a shear-horizontal wave, or a lamb wave, or any combination of shear wave, shear horizontal wave and lamb wave. ### Claim 22 (depends on 18) The method of claim 18, further comprising incorporating islands of floating magnetoelastic (ME) material between at least one pair of electrodes. ### Claim 23 (depends on 18) The method of claim 18, further comprising switching n different multiferroic antennas between m radio-frequency sources or inputs, in response to receiving at least one control voltage in controlling a time varying antenna, in which value n is larger than value m. ### Claim 24 (depends on 23) The method of claim 23, wherein at least a portion of said n different multiferroic antennas are configured for operating at different frequency ranges than one another, toward broadening overall an range of operating frequencies.