Abstract — In this work, we introduce the design and implementation of wideband microwave amplifiers based on “Normalized Gain Function (NGF)” method. Normalized Gain Function is defined as the ratio of desired shape or frequency response of the gain function of the amplifier to be designed and shape of the transistor forward gain function. Synthesis of input/output matching networks (IMN/OMN) of the amplifier require target gain curves as the functions of normalized gain function to be tracked in two sequential nonlinear optimization processes. A prototype low power amplifier circuit is produced and measured to show the usability of the design approach. Index Terms — Microwave amplifiers, Impedance matching, Network synthesis, Optimization, Microwave transistors. I. INTRODUCTION In wideband microwave amplifier design, there is no well- established analytic solution of the amplifier equations composed of many unknown circuit parameters of the input and output matching networks (IMN/OMN). Real Frequency Techniques (RFTs) are known to offer excellent solutions to the microwave amplifier design problems. The reflectance based version called as “Simplified Real Frequency Technique (SRFT)”, is one of the most successful RFT that can be used in wideband filter and microwave amplifier design problems [1-6]. Based on SRFT approach, we have recently introduced in the literature a powerful numerical microwave amplifier design technique, so called NGF (Normalized Gain Function) method for wideband amplifier design applications [1, 5, 6]. NGF takes its name from the amplifier gain function T to be designed, divided by the forward gain function of the transistor |S 21 | 2 , i.e. T N =T/|S 21 | 2 , a kind of normalization or division operation applied to the amplifier gain function T by the normalization factor |S 21 | 2 [1, 5, 6]. NGF is basically used to automatically generate the OMN and IMN target gain functions in terms of normalized gain function T N to be used in two sequential non-linear optimization procedures respectively, that eventually yield driving point Darlington immitance (impedance or admittance) functions Ĩ L (p) (Z L (p) or Y L (p)) and Ĩ G (p) (Z G (p) or Y G (p)) as PRFs (Positive Real Functions), which completes the design [1]. The topology and element values of OMN/IMN are then obtained by executing our high precision Darlington immitance synthesis tools [7, 8]. In this work, the use and success of the NGF method in the design and implementation of wideband microwave amplifiers is discussed. For this purpose design specific application aspects of NGF method and the design implementation are demonstrated by a low-power wideband amplifier design. Various designs have been implemented and measured for testing the robustness of the aproach in realization process by checking the agreement of simulation and measurement results. The implementation and measurement results of a wideband band amplifier design is presented in this work to exhibit the utilization and efficiency of the NGF based amplifier design process. Realized amplifier prototype with IMN and OMN layouts and the performance measurements are presented. After the first theoretical introduction of NGF to the literature in [1] and [5], the first successful NGF based working amplifier prototype was reported in [6], which have specs such that operating band of 0.9-1.5GHz, gain of ~10- 12dB alongside the passband, maximum in-band input/output reflectance of -8.2dB and maximum output power of 63mW. Meanwhile, this paper has come to existence upon further desire of our team to be able to prove the NGF’s capability in design and realization of an amplifier, having a much wider band of ~0.8-2.8GHz utilizing an inductive peaking feedback [9], with a different transistor in the same family, NE3509M04, an HJ-FET from Renesas Electronics Corp. In the paper, after a brief review of NGF basics in section II, section III presents this new NGF based amplifier design together with successful and promising measured performance results of its prototype circuit. II. BRIEF REVIEW OF WIDEBAND MICROWAVE AMPLIFIER DESIGN USING NGF Fig. 1 shows a block diagram of a wideband microwave amplifier whose gain formula is given as [1, 5, 6] 2 2 2 21 2 2 22 1 1 , , 1 1 G L G L G L IN G L T T S T T T S −Γ −Γ = = = −Γ Γ − Γ (1) G G Γ Z IN IN Γ Z OUT OUT Γ Z L L Γ Z G R G E L R Fig. 1. Wideband microwave amplifier block diagram: IMN, OMN: Input/Output matching networks, Q: active device, R G and R L : source and load side resistive terminations [1, 5, 6]. where S ij (i, j=1,2) are the unit normalized scattering parame- Design and Implementation of Wideband Microwave Amplifiers Based on Normalized Gain Function Ramazan Köprü 1 , Sedat Kılınç 2 , Ahmet Aksen 1 , and Binboga Siddik Yarman 2 , Fellow, IEEE 1 Işık Univ., Electrical-Electronics Eng. Dept., Istanbul, ile, ramazan.kopru@isikun.edu.tr , aksen@isikun.edu.tr , 34980, Turkey 2 Istanbul Univ., Electrical-Electronics Eng. Dept., Istanbul, Avcılar, sedat.kilinc@istanbul.edu.tr , yarman@istanbul.edu.tr , 34320, Turkey