Wideband Excitation Technology of <formula formulatype="inline"><tex Notation="TeX">${\rm TE}_{20}$</tex></formula> Mode Substrate Integrated Waveguide (SIW) and Its Applications

Abstract

The higher order mode substrate integrated waveguide (SIW) has advantages in the applications, which are: 1) simplifying the structure with reduced fabrication cost and 2) enhancing the stability of performance by relaxed fabrication tolerance. In this paper, two wideband mode excitation structures are presented and investigated for the SIW. A slot along the mid line in the longitudinal direction of the SIW is employed to convert the electromagnetic field pattern between slotline and the mode SIW. The second structure is based on the slot aperture coupling and can realize wideband direct transition between the mode SIW and microstrip line. Both transitions have a simple and compact structure, as well as broadband characteristics. The wideband transition performance is demonstrated in this paper. As application examples of the transitions, two broadband substrate integrated baluns are presented and fabricated based on the mode excitation structures and mode characteristics. The 180 out-of-phase and equal magnitude of the balun outputs in a wide frequency range can be achieved inherently. The balun based on the slotline excitation has a fractional bandwidth of 50.2%, from 7.3 to 12.2 GHz, with measured return loss, amplitude imbalance, and phase imbalance better than 10 and 0.45 dB and 3.8 . The balun based on the aperture coupling excitation shows a fractional bandwidth of 50.3%, from 7 to 11.7 GHz, with measured return loss, insertion loss, amplitude imbalance, and phase imbalance better than 10, 1, and 0.27 dB and 2.4 , respectively. Both baluns not only show good performance, but also demonstrate the existence of the mode in the SIW.

TE 20 mode substrate integrated waveguide based high gain eight‐beam leaky‐wave antenna for multi‐directional radiation coverage

“…The 50Ω co‐axial probe feeding is used at the input port to feed the four way microstrip power divider which are connected to transitions through step impedance transformers. This power divider is used as a feeding circuitry for TE 20 mode SIW TL and width of the TE 20 mode SIW can be calculated from Equation …”

“…[1][2][3] The utilization of higher order mode of SIW in designing antenna array makes the design compact and also reduces the fabrication cost. 4,5 Besides this, the rapid growth in wireless communications and other surveillance applications demand a new standard having maximum beam-scanning coverage area, compactness, fair gain and so forth. These systems often demand simultaneous multiple beams and beam steering capabilities.…”

Compact bilayer substrate integrated waveguide leaky wave antenna with dumbbell‐shaped slot based on the TE 20 mode

“…Also, the TE 20 mode for designing antenna arrays is a useful approach . Recently, various techniques have been used to excite the higher modes . In this article, the TE 20 mode is excited using an SIW power divider (3‐dB power divider with 180° phase difference).…”

Higher mode SIW excitation technology and its array application

“…A multilayer balun was designed to generate the TE 20 mode of SIW to realize the multimode transmission [7]. Two wideband direct TE 20 mode excitation structures were proposed and measured, both of them can be widely applied in microwave and millimeter-wave circuits and antenna feeding networks [8]. Moreover, there are also some researches in resonant cavity higher mode.…”