The origin of the kink phenomenon of transistor scattering parameter S/sub 22/

Abstract

In this paper, we investigate a new rectangular-fed printed open-slot antenna (POSA) with reflector, which has the advantages of improved radiation-pattern properties along with broad-bandwidth characteristics. The measured bandwidth of the proposed POSA with reflector is approximately 47.6% (Ϫ10 dB Ն S 11 ), thus, it can be used for PCS, DCS, and IMT-2000. But the measured bandwidth of the PCSA with reflector is approximately 46% (with VSWR Յ 2.0). The tilt angle at maximum gain is enhanced by using a modified POSA with reflector for practical applications. The radiation pattern null and distortion of the open-slot antenna exhibited better performances than those of the closed-slot antenna. The back-lobe level of the POSA with reflector also presented much better results than the PCSA with reflector. The proposed antenna obtained not only wider bandwidth but also better radiation patterns characteristics than the PCSA with reflector.ABSTRACT: This paper presents an active broadband-transmitting patch antenna, which works in the 1650 -2300-MHz band to provide GSM-1800 and UMTS services. An increase of the reflection bandwidth of the referenced passive antenna has been achieved due to the resistively equalized broadband-amplifying active antenna. An increase in equivalent isotropic radiated power (EIRP) of 11-12 dB compared to the passive antenna, with a ripple lower than Ϯ0.5 dB, has also been achieved.

Analysis of RF scattering parameters and noise and power performances of RF‐power MOS in 0.15‐μm RF cmos technology for RF SOC applications

“…In addition, we also found that the decrease of the measurement temperature and the increase of the device's width enhanced the kink effect of both S 11 and S 22 (not shown here). The enhancement of the kink phenomenon in the above three cases can be interpreted in terms of the increase of g m [11][12][13][14]. In addition, the enhancement of the kink phenomenon can also be interpreted in terms of poles and zeros [14,15].…”

“…Figure 1(a)-(d) shows the four measured S parameters (S 11 , S 22 , S 12 , and S 21 ) of the RF-power n-MOSFET with 400-m total gate width at V DS ϭ 3 V and various gate-source voltages. The kink phenomena of the S 11 and S 22 of the RF-power MOSFETs can be explained by deriving the input and output impedances (or admittances), respectively, of a four-terminal MOSFET under the measurement conditions of the S parameters [11][12][13][14][15]. Our results show that the input impedance of the RF-power MOSFETs intrinsically shows a simple series-RC circuit at low frequencies and a "shifted" parallel-RC circuit at high frequencies.…”

“…Therefore, in this paper, RF-power n-MOSFETs with various gate widths (400, 800, and 1600 m) fabricated with an advanced 0.15-m RF CMOS technology are used to study the size effect (or g m ) on the kink phenomenon of the scattering parameters S 11 , S 22 , S 21 , and S 12 [11][12][13][14][15]. It is found that either the increase of the device's width or the increase of the gate-source voltage V GS (when its corresponding g m is smaller than the maximum g m ) and the decrease of the measurement temperature can enhance the kink effect of both S 11 and S 22 due to the increase of g m .…”

250 MHz TO 30 GHz, UNILATERAL CIRCUITMODEL FOR INGAP/GAAS HBT

“…Equation (7) is the same formula used in [17,18] with no g o consideration. This proofs the robustness of the formulation.…”

“…However, for the sake of model completeness for the transistor with larger g o , it is included in the formulation. In the case where Y π is much smaller than g m (with g o neglected), (3) will reduced to local series-series feedback concept shown in [13,17,18]. With some necessary circuit elements modification as in (3), emitter resistance is uncoupled.…”