# A Low-Cost Printed Log-Periodic Dipole Array for DVB-T2 Digital TV Applications
## 1 Introduction
Such techniques include using different shapes for the LPDA dipoles [13; 14; 15; 16], using fractal layouts for the dipoles to increase the total length of the current path [17; 18], reducing the axial size of the LPDA by reducing the boom length [19], or using the dielectric-loading technique [20], which can be applied both to wire LPDAs [13; 15] and printed LPDAs [14; 16; 17; 18; 19; 20]. The aim of this paper is to propose a compact and low-cost printed LPDA for DVB-T2 Digital TV applications, covering the whole DVB-T2 UHF band from Channel 21 to Channel 69 (470 MHz-860 MHz). This solution has been achieved by exploiting both the use of a dielectric substrate and the shaping of the radiating dipoles. An FR4 substrate has been chosen since it is one of the cheapest available in the market, and the antenna size has been confined to an A4 sheet dimension, which is the most common and cheapest format of FR4 sheets with a double metal cover. Moreover, the A4 format is also the typical dimension of the working plane of most of the milling machines for the creation of printed circuits, and this reduces the overall production costs. To the best of the authors' knowledge, the solution presented here is not available in the literature, wherein only a few wire LPDAs for DTV in the UHF frequency band can be found [9; 10]. In comparison with these wire LPDAs, the printed LPDA proposed here allows a compact structure, with a significant reduction in the planar size (see, e.g., the wire LPDA in [9], wherein the planar size is 302.6 mm \(\times\) 356 mm vs. 208 mm \(\times\) 289.5 mm of the antenna in this work). As summarized in Table 1, these wire LPDAs have a large size and a higher production cost compared to our proposed solution, which is designed on an FR4 dielectric substrate and fits in an A4 size. Our solution also offers a compact size compared to similar printed LPDAs [4; 11; 14; 16; 17; 19; 20; 21], with a normalized area of only 0.26 \(\lambda^{2}\) (where \(\lambda\) is the free-space wavelength at the central frequency) and a similar (or higher) average gain. Therefore, it is an effective and high-performing LPDA for DTV applications and a valid alternative to the most common wire LPDAs. It should be remarked that LPDA miniaturization within the UHF band in a limited space such as an A4 sheet is not trivial. Hence, a moderate meandering of the radiating dipoles has been implemented to suitably reduce the vertical size. This will obviously increase the dipoles' horizontal size, resulting in a stronger coupling between adjacent dipoles. Therefore, an adequate compromise must be found between the size reduction and the antenna performance. The final design covers the requested bandwidth with a satisfactory far-field pattern in both E- and H-planes and a reasonably flat gain, fulfilling all the specifications of a receiving antenna for DTV services. The proposed LPDA array has been designed using CST Microwave Studio 2023, a general-purpose software for the 3D electromagnetic simulation of microwave components. CST has been a well-assessed and established electromagnetic software for more than two decades, and its results can be considered equivalent to experiments, as reported in the open literature for a wide range of applications (see, for example, [12; 22; 23; 24; 25; 26; 27]). Therefore, we relied on CST for assessing the LPDA performance.