Dual-Frequency Miniaturized Substrate Integrated Waveguide Quarter-Mode Cavity-Backed Antenna Based on Minkowski Fractal Gap with Orthogonal Polarization Radiation Characteristics

<p>Effect of ground size on antenna reflection coefficient: (a) mode <span class="nowrap"><svg height="11.8878pt" id="M21" style="vertical-align:-0.04979992pt" version="1.1" viewbox="-0.0498162 -11.838 24.6583 11.8878" width="24.6583pt" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M673 0V28C608 34 594 43 563 129C499 303 432 494 370 665L339 656L132 132C98 43 84 37 20 28V0H238V28C162 35 154 45 175 108C188 150 203 192 219 237H432C454 176 474 122 487 83S491 36 428 28V0H673ZM418 280H234C265 362 296 450 328 535H330L418 280Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.983,-5.741)"><path d="M729 -138C637 -95 547 -41 484 2C600 37 712 151 712 329C712 532 560 665 390 665C173 665 46 499 46 313C46 210 91 125 155 69C217 10 303 -11 357 -14C482 -102 560 -138 592 -146C623 -155 672 -162 720 -162L729 -138ZM351 29C239 53 151 172 151 340C151 531 256 624 365 624C501 624 607 507 607 303C607 142 529 55 447 31L418 51L351 29Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,15.762,-5.741)"><path d="M871 0V33C783 41 780 45 777 152L768 506C765 610 771 609 860 617V650H683L453 157L228 650H59V617C150 609 154 606 146 481L132 275C124 170 117 125 112 93C105 50 84 39 27 34V0H267V34C200 39 176 48 173 93C170 130 171 172 176 256L190 540H192L414 8H438L682 554H685L689 152C689 45 686 41 604 33V0H871Z"></path></g></svg>;</span> (b) mode <span class="nowrap"><svg height="11.8878pt" id="M22" style="vertical-align:-0.04979992pt" version="1.1" viewbox="-0.0498162 -11.838 23.3143 11.8878" width="23.3143pt" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M372 352C427 368 507 407 507 502C507 548 486 592 451 616C420 638 376 650 301 650H44V622C124 616 128 610 128 527V123C128 40 122 34 36 28V0H257C336 0 402 12 453 40C512 72 548 124 548 191C548 291 471 335 372 350V352ZM213 362V558C213 591 216 602 226 608C235 614 258 618 282 618C377 618 415 558 415 490C415 406 369 362 260 362H213ZM213 328H258C380 328 450 283 450 181C450 76 377 35 296 34C231 34 213 53 213 125V328Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,7.644,-5.741)"><path d="M729 -138C637 -95 547 -41 484 2C600 37 712 151 712 329C712 532 560 665 390 665C173 665 46 499 46 313C46 210 91 125 155 69C217 10 303 -11 357 -14C482 -102 560 -138 592 -146C623 -155 672 -162 720 -162L729 -138ZM351 29C239 53 151 172 151 340C151 531 256 624 365 624C501 624 607 507 607 303C607 142 529 55 447 31L418 51L351 29Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,14.423,-5.741)"><path d="M871 0V33C783 41 780 45 777 152L768 506C765 610 771 609 860 617V650H683L453 157L228 650H59V617C150 609 154 606 146 481L132 275C124 170 117 125 112 93C105 50 84 39 27 34V0H267V34C200 39 176 48 173 93C170 130 171 172 176 256L190 540H192L414 8H438L682 554H685L689 152C689 45 686 41 604 33V0H871Z"></path></g></svg>.</span></p>

International Journal of Antennas and Propagation

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Figure 9

Figure 9: Dual-Frequency Miniaturized Substrate Integrated Waveguide Quarter-Mode Cavity-Backed Antenna Based on Minkowski Fractal Gap with Orthogonal Polarization Radiation Characteristics 

Figure 9 | Dual-Frequency Miniaturized Substrate Integrated Waveguide Quarter-Mode Cavity-Backed Antenna Based on Minkowski Fractal Gap with Orthogonal Polarization Radiation Characteristics 