Abhishek Sahu

To be fully deployed in high-throughput acoustic filter testing environment, pyramid probe cards require accurate characterization and de-embedding techniques. This paper presents a systematic design procedure for an on-wafer Short-Open-Load-Thru (SOLT) calibration kit on lithium niobate substrates for filter measurements using pyramid probe cards. First, the propagation velocity of the lithium niobate substrate is extracted from a transmission line measurement based characterization methodology. Next, the coefficient of the Thru standard is calculated using the propagation velocity. A Line-Reflect-Reflect-Match (LRRM) based self-calibration algorithm and the partially known standards can then be used to remove the errors associated with the pyramid probe card. The coefficients of the remaining standards of the on-wafer calibration kit are finally extracted employing the calibrated probe card. As the test fixture itself is utilized to characterize the on-wafer calibration kit, the need of additional fixtures and measurements is eliminated. The effectiveness of the on-wafer calibration is validated by performing repeatable measurements of state-of-the-art filters fabricated on lithium niobate substrate and comparing with other calibration approaches such as port extension and off-wafer calibration using impedance standard substrate (ISS). We demonstrate that the on-wafer calibration kit offers comparable performance in terms of in-band loss and out-of-band rejection.

This paper presents a dual-band filter using complementary split ring resonators (CSRRs) based on slow-wave substrate integrated waveguide (SIW) technology. Compared to conventional SIW the proposed topology includes internal metalized vias connected to the bottom metalized layer thus confining the electric fields in the upper layer, while the magnetic field is present throughout the whole substrate. By loading CSRRs on the top metal surface of this slow-wave medium, two pass bands propagating below the waveguide cutoff frequency can be generated. This novel topology allows relatively independent control over the centre frequency by tuning the internal metalized via heights and separation of CSRRs. Finite-element based electromagnetic simulations show that, the filter offers several advantages in terms of compact size, good selectivity and stopband rejection, as well as frequency tunability.

In this paper we present the design of a millimeter-wave antenna based on recently developed ridge gap waveguide (RWG) technology. This is the first antenna designed based on this technology to operate in V-band (45-70 GHz). The antenna operates at 68.7 GHz with a bandwidth of 900 MHz. The feed network consists of a quarter-wavelength ridge gap waveguide resonator that excites a slot in the top metal plate. The corners of the slot are optimized for improved impedance matching. The simulated antenna has a gain of 7.0 dBi and an input reflection coefficient of -20.8 dB. Finite-element based electromagnetic simulations show that it is possible to scale ridge gap waveguide designs to operate in V-band.

The use of substrate integrated waveguides (SIW) for microwave and millimeter wave integrated components has increased dramatically over the last decade. They mimic the performance of conventional metallic waveguides and they are fabricated using printed circuit boards using the top and bottom metallization with two rows of vias forming the side walls. This creates a low profile, compact, and light weight alternative to conventional metallic waveguides, and they allow a direct interconnection with printed circuit boards and active components. This article reviews the fundamental theory, documents the research that has been performed over the past decade, and summarizes progress up to the recent state-of-the-art including novel SIW structures for passive circuits and antennas as well as new applications for reconfigurable and printed circuits using SIW technology. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:129–145, 2016.