Compact 60 GHz low‐temperature cofired ceramic filter with quasi‐elliptic bandpass response

Abstract

This study presents a 60 GHz quasi-elliptic bandpass filter with a compact and planar structure. The proposed filter was constructed by stacking substrate integrated waveguide (SIW) cavities on the central transverse plane of a shielding SIW cavity. Jerusalem cross (JC) apertures and circular apertures were etched on the metal layers of the stacked SIW cavities to enable dual-mode operation and energy coupling. In the dual-mode cavities, the TM 110 cavity mode and JC aperture mode can be excited simultaneously. Cross-mutual couplings exist among the resonant modes, resulting in two finite transmission zeros with each at either side of the passband. Multilayer low-temperature cofired ceramic technology was adopted to manufacture the experimental filter. The measured centre frequency was 60 GHz at a fractional bandwidth of 4.5% with two finite transmission zeros located at 53.7 and 65 GHz, thereby achieving highfrequency selectivity.

Second-Order Mixed Coupling Filter With One Controllable Transmission Zero Using Multilayer Substrate Integrated Waveguide

“…3 that the TZ appears to be closely associated with the even mode, and this property can be explored for designing mixed coupling filters with an asymmetrical frequency response. Based on the extracted odd-and even-frequencies, the electric coupling coefficient E c , magnetic coupling coefficient M c , and the total coupling coefficient k a can be obtained by the proposed procedures and Equations (14)- (15) in [7]. It is obvious that the changes of the odd mode and transmission zero frequencies lead to the changes of E c and M c .…”

“…In [5,6], the implementation of the mixed electric and magnetic coupling SIW filters with TZs for high selectivity have been reported, in which an inductive window between two SIW resonators introduces the magnetic coupling, and an embedded short-ended strip is employed to create the electric coupling, however, this filter is relatively large not only because of its planar arranging structure, but also due to suffering from the structure complexity and lack of flexibility, and there will be radiation loss if it operated in millimeter-wave bands. The application of SIW technology makes the realization of filters with the multilayer structure and compact size possible in [7][8][9][10][11][12]. The coupling between the vertically stacked SIW resonators can be introduced by etching the apertures with different sizes, positions and number on the middle metal layer.…”

Accelerated multiobjective design of miniaturized microwave components by means of nested kriging surrogates

“…Miniaturization of microwave components has become an important design consideration due to the emergence of space‐limited applications, including mobile communications, wearable/implantable devices, sensors, biomedicine, body area networks, and so forth. Compact implementations of microwave circuits can be achieved in various ways; some of the popular techniques include utilization of high‐permittivity substrates, transmission line (TL) folding, employing the slow‐wave phenomenon, in particular, replacing conventional TLs by their shorter counterparts (eg, compact microwave resonant cells, CMRCs), or multilayer realizations (eg, low temperature cofired ceramic technology). Clearly, miniaturized circuits tend to feature complex topologies that normally have to be evaluated using full‐wave electromagnetic (EM) analysis.…”

Low‐cost multi‐criteria design optimization of compact microwave passives using constrained surrogates and dimensionality reduction

“…10 A number of techniques have been developed to permit compact realization of microwave passives. Some of these methods include implementation on high-permittivity substrates, 11 folding of conventional transmission lines (TLs), 12 multilayered circuits (e.g., low-temperature cofired ceramic (LTCC) technology 13,14 ), and utilization of slow-wave phenomenon where the traditional TLs are replaced by the abbreviated components (e.g., compact microwave resonant cells, CMRCs). 15,16 The aforementioned techniques typically imply the increase of the circuit complexity and the appearance of electromagnetic (EM) cross-coupling effects, which cannot be accounted for using circuit theory means, in particular, equivalent network models.…”