Design and optimization of 3-D compact stripline and microstrip Bluetooth/WLAN balun architectures using the design of experiments technique

Abstract

Abstract-In this paper, various architectures of 3D compact microwave balanced to unbalanced (balun) transformers for Bluetooth/WiFi antenna applications are successfully designed and optimized using the Design of Experiments (DOE) approach. Two different multilayer topologies, one microstrip and one stripline, are investigated on Low Temperature Co-fired Ceramic (LTCC) substrate. The design goals for both baluns are perfectly balanced outputs from 2 to 3 GHz and a resonant frequency of exactly 2.4 GHz. It is demonstrated, using only eight simulations, that perfectly balanced outputs are not possible under the given conditions in the case of the microstrip balun. Nevertheless, the stripline balun can be optimized due to its almost symmetrical structure, and both simulations and measurement results verify the conclusions. The DOE method is very simple to implement and gives a clear understanding of the system behavior at the beginning of the design process, reducing the amount of work required for achieving the design goals by orders of magnitude compared to the widely used trial-and-error approach. The matching and unique measurement issues regarding the calibration, placement of probes and the deembedding of the microstrip to coplanar waveguide (CPW) transitions are discussed in detail for the optimized stripline balun. This technique can be easily applied to the fast and efficient optimization of complicated radiation structures, such as reconfigurable or multilayer mutliband antenna arrays.

Broadband Vertical Transitions Between Double-Sided Parallel-Strip Line and Coplanar Waveguide

“…However, they are suitable for circuit design instead, and using such transitions to feed antennas will degrade the antenna performance [4]. The optimizations of planar transitions using different techniques have already been reported [10][11][12][13].…”

Semi-lumped Balun Transformer using Coupled LC Resonators

“…Many RF circuit modules and systems adopt a balanced input and output in order to improve the dynamic range by reducing the noise and even order harmonics [1][2][3][4][5][6]. As these RF modules and systems advance to be become smaller, lighter, and multi-functional with better performance, they generate a strong need for compact sized wideband balun devices [3][4][5][7][8][9][10][11][12][13][14][15][16][17].…”

“…It is applied to low temperature cofired ceramics, multi-layered ceramics, and microwave integrated circuit chips and modules because it has a simple structure, sufficiently large bandwidth, and a reasonable phase difference and power distribution [7-9, 11, 13, 14, 16-18]. These modified Marchand balun consists of four quarter-wave length coupled lines which are implemented as a meander-shaped line [8,14] or spiral-shaped line for miniaturization [7,9,16]. The LC resonance and stepped impedance methods were also proposed to reduce the physical length of the utilized coupled line [11,13].…”

Broadband balun based on three coupled transmission lines

“…Недостаток данного устройства -большие габариты. С целью улучшения рабочих параметров и уменьшения габаритов сим-ШИРОКОПОЛОСНОЕ СОГЛАСУЮЩЕ-СИММЕТРИРУЮЩЕЕ УСТРОЙСТВО… 51 метрирующие устройства претерпели ряд изменений [2][3]. В источнике [3] опи-сано миниатюризированное симметрирующее устройство на двух связанных от-резках линий передачи длиной / 8  .…”