Additively Fabricated Air-Filled Waveguide Integrated With Printed Circuit Board Using a Through-Patch Transition

Abstract

The hybrid integration of an additively fabricated air-filled waveguide (WG) with a printed circuit board (PCB) is presented. An arrangement is proposed where different waveguiding structures share the same common metal plane on PCB. Such an approach allows combining the low-loss and high-Q properties of an air-filled waveguide, active circuit realization of the strip transmission line, and 3-D capabilities of additive manufacturing. A broadband transition is developed employing a through-patch coupling interface from a microstrip (MS) line to a waveguide. The concept was experimentally validated with exemplary transitions operating within X-band and K -band, featuring a measured bandwidth of f h / f l ≈ 1.4 and average pertransition loss including connecting lines of ∼1.2 and ∼1.9 dB, respectively.

Wideband Microstrip to 3-D-Printed Air-Filled Waveguide Transition Using a Radiation Probe

“…Within the per transition loss, it is estimated that ∼0.4 dB of loss is due to the coax-to-MS launcher. The total waveguide length between end shorts within the demonstrator is 85 mm (estimated loss of ∼0.1 dB/cm [5]).…”

“…On the other hand, vertical transitions [3], [4] enforce the perpendicular orientation of the microstrip and waveguide, leading to integration limitations. Recently, an air-filled waveguide, integrated with the PCB by sharing the common metal plane, which on one side serves as a ground plane for the microstrip transmission Manuscript received 28 January 2022; revised 28 March 2022 and 19 April line and on the other side as one of the walls of the waveguide, has been proposed [5] as an alternate to the above arrangements. Apart from low-cost manufacturing, low weight, and high compactness, a great advantage of such realization is the ease of integration of low-loss passive waveguide/microstrip and active microstrip components.…”

“…In this letter, we propose a wideband microstrip-towaveguide transition that exploits to a great extent the 3-D-printing fabrication with selective metal deposition and exceeds the bandwidth capability of one in [5]. To launch the EM wave into the waveguide, a radiation probe, protruding from the microstrip line, is introduced at an offset from the shorted end of the waveguide and the open end of the microstrip line.…”

Low-cost fully additively manufactured passive microwave components exploiting available 3D flexibility

“…Recent advances in mechanical engineering have enabled obtaining a printing resolution of tens of micrometer, which is of the same order as Aerosol Jet Printing (AJP) 17 , 18 at a fraction of the AJP cost. One of the potential applications for which the VP technology might be well suited is the realization of microwave components 19 , 20 when coupled with suitable (non)selective metallization technique. Post-processing of printed parts is necessary as they are made of non-conductive polymer.…”

Compact Microstrip Line to Rectangular Waveguide Transition Using Corrugated Substrate Integrated Waveguide

“…In [8], the MSL and the Empty substrate integrated waveguide (ESIW) are coupled through a circular gap and a cylindrical filament with the same center; the methodology is further applied to MSL-to-RWG transitions. In [9], the MSL-to-RWG transition is realized by through ground patch coupling, and a waveguide step is used for broadband matching. In [10], a radiation probe is employed for coupling.…”