A Y-junction circulator based on empty substrate integrated coaxial line (ESICL) technology is proposed in this paper. As ESICL is a novel transmission line, many of the common waveguide devices have not yet been developed in this technology, i.e., only filters, a power divider, a 90° hybrid directional coupler or transition structures have been presented but no nonreciprocal devices. In this paper, a ferrite-based circulator has been designed and fabricated to operate at a central frequency of 12 GHz. Measurements performed with the help of an electromagnet confirms the stability of the circulator response under different DC biasing fields. Also, measurements with magnets have been done to integrate the circulator in communication systems. In addition, different temperature tests from 20° C to 90°C have been carried out with the aim of checking the scattering parameters variations. The experimental results confirm the results obtained by the full wave simulations: insertion loss better than -1 dB isolation and return loss below -10 dB from 10 to 14 GHz.

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Low Loss Ferrite Y-Junction Circulator Based on Empty Substrate Integrated Coaxial Line at Ku-Band

We propose here a method to design monolithic dielectric filters (MDF) for achieving new levels of performance. The filter consists of a high-permittivity dielectric slab placed in a waveguide below cutoff loaded with low-permittivity dielectric slabs. These filters are miniature, highly selective, with low losses and small level parasitic resonances. A new approach is based on the equivalent circuits used to model the waveguide dielectric resonator of the monolithic filter. This model shows how the resonance frequency and coupling coefficient can be applied to synthesize a prescribed passband having Chebyshev or maximally flat characteristics. Experimental results are presented in S- and X-band showing good agreement with the theory.

Monolithic dielectric filters in integrated waveguide technology

A simple Ka-band Y-circulator is presented, fabricated according to integrated waveguide technology (INWATE). The performance is as follows: 20 dB isolation bandwidth of 20%, and return loss and insertion loss about 20 dB and 0.5 dB, respectively. This type of circulator seems to be well suited to form part of future INWATE circuits.

C. Schieblich

Papers

Ka-band Y-circulators in integrated waveguide technology