An 84 GHz DAT-based power amplifier with 18 dBm utilizing an ultra-symmetric dual-differential power divider - Paper abstract

Sep 17, 2026

An ultra-symmetric dual-differential power divider based on low-loss CPW transmission lines and transformers is presented for distributed active transformer (DAT) based power amplifiers (PAs). Two millimeter-wave PAs using different power dividers are compared through insertion-loss analysis and full measurements. At 84 GHz, the PA2 employing the proposed divider attains 18 dBm saturated output power, exceeding PA1 by 1.35 dB. PA2 achieves 24.4 dB power gain and 12.63% power-added efficiency while occupying 0.48 mm² die area.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages4

Reading Time10 min

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1. Introduction

2. Dual-differential power divider

This article has been accepted and published on J-STAGE in advance of copyediting. Content is final as presented. IEICE Electronics Express, Vol.VV, No.NN, 1–4 LETTER An 84 GHz DAT-based power amplifier with 18 dBm 􀁖 􀁳􀁡􀁴 utilizing an ultra-symmetric dual-differential power divider Linhong Li1,2 , Shuai Cheng1,2 , and Zhaofeng Zhang1a) Abstract An ultra-symmetric dual-differential power divider based on the low loss CPW and transformer for the distributed active transformer (DAT) based power amplifiers (PA) has been introduced in this Letter. Two millimeter-wave PAs with different power dividers are compared. Experimental results show that the PA2 with the proposed power divider achieves 18 dBm saturated output power (􀀥 􀁂􀀰􀁃) at 84 GHz, which exceeds that of the PA1 with the typical dual-differential power divider by 1.35 dB. The power gain and power-added efficiency (PAE) of PA2 are 24.4 dB and 12.63%, respectively. The PA2 occupies a die area of 0 .48 􀀼􀀼2 . key words: power amplifiers, power divider, millimetre wave, CPW Classification: Microwave and millimeter-wave devices, circuits, and modules 1. Introduction The low breakdown voltage of CMOS-based devices is oneof the main obstacles for achieving a PA with high output power, especially in the millimeter-wave band where the capacitance of large devices becomes prohibitive [1] . Thus, even though multi-way power combining will lead to severe parasitics, metal loss, and mismatch problems, it is widely used to enhance the PA output power. Distributed active transformers (DAT) exhibit an excellent performance among various power combiners [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12] . However, this DAT-based PA needs a dual-differential power divider with at least a bend. Previous studies [3, 7, 13] introduced the satisfying power divider shown in Fig. 1 (a), and some improvements [14] have been proposed on the differential lines to minimize the imbalance and reduce the undesirable mutual coupling between the combiner and divider. However, the structure is asymmetric, and the model of the curved differential lines is still unclear and cannot be designed simply by equal lengths, which degrades the balance of the output differential signal and deteriorates both the output power and power gain of the PA. Although using two Wilkinson power dividers can achieve a balanced dual-differential power divider, the use of multiple quarter 1Dept. of Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China 2University of Chinese Academy of Sciences, Beijing, China a) [zhangzf@sari.ac.cn](zhangzf@sari.ac.cn) DOI: 10. 1587/elex.19.20220236 Received May 17, 2022 Accepted May 23, 2022 Publicized May 31, 2022 wavelengths increases the size of the circuit. Fig. 1. (a) Previously reported dual-differential power divider in HFSS.(b) Proposed dual-differential power divider in HFSS. (c) Insertion loss at each port of the power divider in (a) . (d) Insertion loss at each port of the power divider in (b) . This Letter reports an ultra-symmetric dual-differential power divider with two transformers [15, 16, 17] and low loss coplanar waveguide (CPW) transmission lines [18, 19] . This proposed divider is shown in Fig. 1 (b) . The insertion loss simulation results of the two power dividers (Fig. 1 (a) and Fig. 1 (b)) are analyzed to obtain the optimal structure. Furthermore, two PAs with two different power dividers are implemented and measured in terms ofS parameters, output power, power gain, and power-added efficiency (PAE) . Experimental results show that at 84 GHz, the saturated output power (􀀥 􀁂􀀰􀁃) of the PA2 (using the proposed ultra-symmetric power divider) is 18 dBm, which is 1.35 dB higher than that of the PA1 (using the previously reported power divider) . 2. Dual-differential power divider The main objective of this Letter is to improve the performance of the DAT-based PA by optimizing the signal balance. An ultra-symmetric dual-differenti

FAQs

What is the main purpose of the proposed work?

The work aims to improve DAT-based power amplifier performance by optimizing the balance of signals using an ultra-symmetric dual-differential power divider.

How is the proposed dual-differential power divider implemented?

It uses two transformers combined with a low-loss CPW section inserted between them to achieve impedance matching and a symmetric layout for DAT-based PAs.

What performance gains are reported at 84 GHz?

At 84 GHz, PA2 reaches 18 dBm saturated output power, which is 1.35 dB higher than PA1; PA2 also reports 24.4 dB power gain and 12.63% PAE.

Sep 17, 2026

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