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K-band low-noise amplifier (LNA) chips are integrated in low-permittivity coplanar waveguide (CPW) and microstrip (MS) structures and are interconnected with substrate integrated waveguide (SIW) ports for direct applications in hybrid SIW technology. A commercial Hittite LNA chip is employed, and special transitions provide the interface between CPW or MS and SIW. The LNA with SIW-to-CPW transitions achieves more than 20 dB gain between 18 and 26.5 GHz, and input/output return losses remain below 10 dB between 21.5 and 26.5 GHz. Related design values for the LNA integration within SIW-to- MS transitions are: the gain is greater than 21 dB; the input/output return loss is better than 12 dB over the entire frequency range. Measurements of a back-to-back SIW-to-CPW transition are provided to put these values in perspective. The maximum noise figures are measured to be better than 4.6 and 4.2 dB, respectively, between 18 and 26.5 GHz. A comparison with measurements performed with an evaluation board supplied by the LNA manufacturer demonstrates successful K-band LNA chip integrations within CPW/MS and SIW. [ABSTRACT FROM AUTHOR]

To achieve broadband performances in the millimeter-wave range, antipodal linearly tapered slot antenna (ALTSA) designs with new combined substrate integrated waveguide (SIW) and regular coplanar waveguide (CPW) feeds are presented and studied. This feed structure eliminates the fabrication of air bridges in direct CPW-fed tapered slot antennas (TSAs). Two millimeter-wave design techniques are introduced for the selected 41–61 GHz and 90–120 GHz frequency ranges, demonstrating very good impedance match and nearly constant gain, beamwidth, and cross-polarization levels over bandwidths of 39% and 28%, respectively. The design procedure is validated by comparing simulated results with measurements performed on a 21–31 GHz (38% bandwidth) prototype. Very good agreement between measured and calculated performance characteristics is obtained with only cross-polarization levels slightly higher than predicted. The structural design parameters and dimensions of all three designs are given. [ABSTRACT FROM AUTHOR]