Fabrication of monoblock ceramic bandpass filters with attenuation poles

Abstract

Ž . Figure 2 Conversion gain of modified top, QUBMIX8 and un-Ž . modified mixer bottom, QUBMIX6 versus IF frequency Figure 3 MMIC mixer photographs the gate bias was V s y0.8 V, the drain bias was V s g d3.5 V, the LO power was LO s 11 dBm, and the LO frequency was 64 GHz. The differences seen between measurement and simulation are due to uncertainties in determining the absolute values of the peak transconductance G . m CONCLUSIONSA new expression for the influence of the via hole inductance on mixer performance has been presented and validated by numerical simulation and by measurement. Theoretical considerations suggest that the conversion gain may be de-creased by as much as 9 dB due to the effects of the via hole inductance. A method for counteracting this effect is introduced which, instead of reducing the wafer thickness, eliminates the reactance of the via hole by resonating it with open-circuit stubs. This is confirmed by measurement, which shows an improvement in conversion gain of 3.5 dB. ACKNOWLEDGMENT Ž . Thanks go to Derek Smith of OMMIC PML for access to the ED02AH foundry. Analysis of the source inductance effect on the power performance of high development HEMT's in Ka-band, IEEE Mi-Ž . crowave Guided Wave Lett 5 1995 , 243᎐245. 4. R. Allam, C. Kolanowski, J.M. Paillot, C. Duvanaud, and Y. Crosnier, Influence of the source inductance parasitic effect on the conversion gain of an HEMT gate mixer, Microwave Opt Ž . ABSTRACT: Small size and rapid attenuation rate are two important factors in the selection of bandpass filters for practical applications. This paper describes a monoblock and modified Chebyshe¨-type bandpass filter with an attenuation pole in the lower stopband. The equi¨alent circuit consists of resonators, and series capacitance is presented to predict the filter performance. The series capacitance is made directly by an appropriate choice of the electrode pattern. Since no additional lumped element is needed, the designed filter shows a simple structure. Also, a compact monoblock bandpass filter using high-permitti¨ity ce-( ) ramics of Ba,Sr O᎐Sm O ᎐4.7TiO is fabricated. Experimental results 2 3 2 of the fabricated filter measured by an HP8510B network analyzer¨erify the expected effect. ᮊ